The longer that couples are together, the more they start to resemble one another—and there is some actual science behind this theory. The phenomenon is known as "convergence of appearance," and it states that if couples who didn't start out looking alike remain together for over 25 years, then they will begin to resemble one another.

There is a component way down in the human DNA that tells us while opposites attract, similarly-looking and like-minded people are the ones that want to make us eventually reproduce. As time soldiers on, even couples' gut and immune systems will start to sync up because of their similar lifestyle choices.

People literally start to morph into their better half.

High profile couples seem to be incredible examples of this morphing phenomenon. Some of them, the ones who have stood the test of time, really are looking a lot more alike than they did in their younger years.

Others don't have the years behind them quite yet, but we know that with a few more decades, they will pretty much be twins because they already look strikingly similar to each other.

Here are twenty-two Hollywood couples who look incredibly close in appearance.  From their jawlines to their smoldering smirks, these couples could very well pass for siblings, not romantically linked partners!

22 Christina Aguilera And Matt Rutler

We won't lie, we didn't think that pop princess Christina Aguilera and her second husband Matt Rutler had half a chance at making it, but here they are years later, still standing side by side. The longer these two spend married, they more they seem to morph into the one another.

If you take away the differently colored hair, and the fact that they are different genders, Christina and her hubby Matt are already pretty much the same person. They even smile and pose on the red carpet in identical ways. We have to admit; they make a pretty adorable pair.

21 Jenifer Lopez And Alex Rodriguez

The ever-dynamic entertainer Jenifer Lopez and her current beau Alex Rodriguez are just like Barbie and Ken. Their perfect tan and toned skin, their dreamy smiles, and fit bodies make us wonder how much more these two beautiful humans could resemble one another.

It's a little bit of a wonder that these two never managed to find their way into each other's arms before now. Looking at them makes you think that they should have been together from the very start. We are so glad that they finally managed to get together so we could stare at their twinning glory.

20 Alexis Bledel And Vincent Kartheiser

Two porcelain dolls make a magical couple. New parents Alexis Bledel and Vincent Kartheiser occasionally give us something magnificent to look at, but other than that they try and keep us guessing. They are one of the most private couples in Hollywood, and unlike many other public pairs, these two hold their relationship cards tightly to their chests.

Bledel met her future husband while working on the set of Mad Men. They became a couple after the wrapping up of season five, but we didn't know a thing about until they made their red carpet debut at the Macallan Masters of Photography collection later that year.

19 Lisa Bonet And Jason Momoa

Actress Lisa Bonet only marries guys who could very well be her twins and are also undeniably attractive in their own right. First, she married rocker Lenny Kravitz, who is the father of her grown daughter Zoe. Those two looked strikingly alike but weren't destined to make it to forever.

Bonet then went and married everyone's favorite Aquaman, who resembles the beauty even more! Bonet and Jason Momoa manage to get everything right, from their undeniable connection and chemistry to their co-parenting awesomeness with Kravitz and their vibing boho styles. Everything they do makes us say, "Yep. These two right here are total relationship goals."

18 Denzel And Pauletta Washington

We have heard many times that couples who spend many years together will start to resemble each other at a certain point. That seems to be the case with Denzel and his longtime partner, actress Pauletta. This celebrity couple has been joined at the hip for over three decades after meeting and working together on the set of Wilma back in 1977!

Together they have raised a family to adulthood and worked to elevate Denzel's acting to its highest possible platform. There are plenty of couples who make great teams in life, but these two set that bar extremely high.

17 Rooney Mara And Joaquin Phoenix

They are both a bit eccentric and super talented and have that dark hair and piercing stare. They also have similar eyebrows and facial features. Looking at each of these actors separately, you would not peg their partner as a look-a-like duo, but put them side by side and the commonalities are undeniable.

The broody couple met while acting on the set of Mary Magdalene and are by all accounts wholly and entirely in love. That said, they are in no rush to the altar. The couple never plans on marrying because they believe that marriage is too mainstream for them. It worked for Kurt and Goldie, so maybe it will work for these two!

16 Kevin Bacon And Kyra Sedgwick

First and foremost, we love this celebrity couple. They had stood the test of time, and each of them has only gotten better looking over the years. They first locked eyes in 1988 while filming the flick Lemon Sky. Kyra was only 22 years old at the time and didn't feel the instant attraction to Bacon. He won her over in the end though.

Now that they are entering the golden stage of life, they are even more stunning. Kevin Bacon particularly has always had a unique look, so it is especially interesting and quite fascinating that he found and married the only other person in Hollywood that could pass as his twin.

15 Mario Lopez And Courtney Mazza

These proud parents have those lovely smiling eyes, dark features, and perfect skin. How lucky are their daughters to have scored the genetic lottery on not one, but BOTH sides of the gene pool. But Lopez didn't appear that lucky in love before meeting and falling for Mazza.

According to Us Weekly, Lopez had previously been engaged to actress Ali Landry, but that relationship hit the skids thanks to Lopez's disappointing decisions. It's pretty evident that Landry simply was not Mario's Cinderella, because his relationship with his wife and mother of his children has been nothing but smooth sailing.

14 Gisele Bundchen And Tom Brady

They both have those perfectly chiseled cheekbones and that sunkissed, sandy blonde hair. They are tall, athletic, and divine specimens of human beings. Brady is, of course, the master at his sport and Gisele rocks the runway like no one else in the biz. These two seem made for one another.

These days Tom and Gisele are happily married and busy raising their family after being set up by a mutual friend in 2006. The beginning to their fairytale romance was rocky, but the couple has managed to weather the ups and downs better than most. The stunners are the proud parents to a son and a daughter as well as an older son that Tom shares with his ex-partner Bridget Moynahan.

13 LeAnn Rimes And Eddie Cibrian

Their almond-shaped eyes and smirky smiles are the same. If they did a face swap, there would be no difference in how they looked. This couple started on a super rocky, and kind of sketchy path. When they met on the set of Northern Lights, both Cibrian and Rimes were husband and wife to other people.

Regardless of how they began, these two have proved over the years that their love is here to stay. We are happy that they seem to be in it for the long haul because now we can not see either of them alongside anyone else. The couple spends their time focused on Eddie's two sons, whom he shares with his ex-wife Brandi Glanville.

12 Rande Gerber And Cindy Crawford

It seemed an impossible task: to find a man that could stand next to the beauty that is supermodel Cindy Crawford. Somehow entertainment industry businessman Randi Gerber found himself up for the task, and the rest is history.

Gerber and Crawford have forever found themselves plagued with rumors of billion-dollar splits, but they seem to take all the gossip in stride because, at the end of the day, the pair are still together. They married in 1998 and have two equally beautiful children together. After over twenty years together, this couple proves that you can make a marriage last in Hollywood.

11 Justin Timberlake And Jessica Biel

Pop music's golden boy Justin Timberlake married his longtime love, actress Jessica Biel, in a lavish ceremony several years ago and they are now loving parents to an adorable son named Silas. Now that the pair has reached "longtime couple status," they are starting to look like one another.

They seem to have similar fashion styles. They are often seen rocking casual looks during the day, neither is very fussy with their clothes, and both enjoy active lifestyles, but they transform come night. When you see this married pair walk the red carpet, your jaw will almost always hit the floor. They clean up well that's for sure!

10 Sophie Hunter And Benedict Cumberbatch

Well, aren't these guys two talented statues who got cut from the same cloth? Pretty sure it's the angular jawline and similarly shaped eyes that make us need to do a double take when we look at them. This couple could probably pass for a pair of siblings.

Cumberbatch and his leading lady Sophie Hunter used their seemingly similar good looks to create little mini me's. The couple currently has two young sons that forever keep them on their toes. We are sure that the entire family closely resembles one another. How could the kids not look like their parents with such strong genes swirling on both sides of the DNA?

9 Blake Lively And Ryan Reynolds

Ryan Reynolds and his superstar wife Blake Lively are equally beautiful blondes. They also both possess loads of acting talent as well as great senses of humor, making them a match made in Hollywood heaven. Whenever we see them together, they appear to be in love, relaxed and thoroughly enjoying the ride. How can they not be? Their work lives are better than ever, they have two gorgeous children to snuggle up with at night.

Plus, each of them can claim that their spouse is the best-looking person on the entire planet. Mr. and Mrs. Reynolds are winning at this game we call life and looking nearly identical while doing it.

8 Seth Meyers And Alexi Ashe

The Late Night host has been married to his wife, Alexi Ashe, for just over five years now. By the time these two hit their thirtieth wedding anniversary, they should be identical. They are already halfway there! The couple has very similar facial characteristics in the mouth, nose and even their eyes.

Meyers married his true love, a human rights lawyer, in a magical summer ceremony on the Massachusetts island of Martha’s Vineyard, as reported by Vogue magazine. Five years later they are enjoying the family life. The couple has two sons so far. Older brother Ashe is two and younger sibling Axel is almost one year old.

7 Jeremiah Brent And Nate Berkus

These two fancy fellows are total twins in their style. Their crisp clothing choices and perfectly coiffed hairstyles are one and the same. They also have a similar bone structure, piercing eyes, and smug smiles for the camera. These two dads are definitely taking style notes from one another. They aren't just working on their fantastic style these days though; the couple is busy building their brood.

According to People magazine, they have recently welcomed another child into their happy home, bringing their bundle of joy total up to two youngsters now. We know that those kids are going to grow up to be the best-dressed kids in all of Hollywood.

6 Maggie Gyllenhaal & Peter Sarsgaard

The ever chill and relaxed couple that is Maggie Gyllenhaal and Peter Sarsgaard has us all wondering if less is more. The private, boho pair often imitate one another in their trendy, yet casual style. One has to wonder, do these two wake up looking this fabulous? It seems so. It is a rare occasion that we see either of them glammed up for the cameras.

They very much prefer the bohemian look, so much so that their Park Slope Brownstone home is an exact reflection of the pair personal style. When it comes to cool, these two match each other perfectly.

5 Dwyane Wade And Gabrielle Union

It hasn't always been a smooth ride for these two, but basketball great Dwyane Wade and his talented actress wife Gabrielle Union have finally hit their stride. According to The Insider, they first met in 2006, just one year after Union became a single woman. Wade eventually split from his former wife, and by 2009 they were the "it" couple.

They took some time apart in 2013, but then came back strong with some bling, an engagement, and a fantasy wedding. This past November they made their ultimate dream come true when they welcomed their little girl into the world. So who does the little one look like? Both parents of course! Especially since they resemble each other so closely.

4 Courteney Cox And Johnny McDaid

Two words for you all: those eyes! Both beauties have those icy blue eyes that manage to stare directly into one's soul. Their fair complexions compliment their dark hair, making them the fairest couple in all of the land.

According to The Daily Mail, Cox has been with her rocker beau since 2013 and engaged to him since 2014. They had a brief moment of separation but reunited in 2015 and seem to have no plans to go anywhere soon. They also have to plans to make things official; Cox has revealed that in interviews, she already feels married in her heart. So sweet.

3 Jennifer Esposito And Louis Dowler

For so long, actress Jen Esposito was primarily known as Bradley Cooper's ex-wife. She did move eventually move on from that relationship and got hitched to her look-alike man, Louis Dowler.

That relationship hit the skids too after only a couple of years, but during their time together Esposito and Dowler started to morph into the same person in terms of looks. If he worked at growing his hair out just a few more inches, they could probably have started visiting the same stylist! Sadly, even couples with dueling great hair aren't a sure thing. They divorced in 2016.

2 Jessica Alba And Cash Warren

Jessica Alba and Cash Warren recently celebrated ten years of marriage, which is forever in Hollywood relationship years. According to People, they spent a bit of time at a spa in Beverly Hills and out to dinner to celebrate the milestone. Chances are they don't get all that much time away now that they are parents to two rapidly-growing daughters and one infant son.

And with their matching brown hair and dark eyes, we have to wonder how their middle child ended up with fiery red locks? She certainly didn't get that coloring directly from her mama or her papa!

1 Nikki Reed And Ian Somerhalder

This adorable married Hollywood couple has tons in common. For starters, they are both stars of major vampire flicks, they also have mad love for their little daughter, and lastly, they have some of the best eyebrows in the game.

Actress Nikki Reed and her hunky husband Ian Somerhalder have very similar features, that much is obvious. It probably isn't their twinning styles that keep them together though, so thank goodness for all the other like interests and loves that the pair shares. They sure do make a good looking couple, whether they are rocking fangs or going without! Never change you two.

Sources: Redbook Mag, InStyle, Us Magazine, Vogue, People, This is Insider, Daily Mail

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