Smiling is a natural thing; in fact studies tell us that it actually takes fewer muscles to smile than to frown. So why isn’t everyone smiling all the time; especially these celebrities that have everything they could ever want? There are in fact a number of celebrities who never seem to crack a smile, whether it is on the red carpet, via social media or for the paparazzi. While some of these celebs have come out and told us why they never want to crack a grin, some of their lips remained sealed when asked.

From not wanting to get wrinkles to having a responsibility to the fashion world to it simply feeling unnatural; the excuses for not smiling are truly weird and unusual. From hot and dreamy Leo with his stoic face to Megan Fox who not only looks sour faced but rumor has it is tough to work with; these A-list celebrities don’t seem to crack a smile for anyone. Here are 12 celebrities who manage to keep a straight face whenever they are photographed.

12. Victoria Beckham

Successful stores, a dreamy husband, a next door neighbor who is a fashion icon and four adorable children; one has to wonder why Victoria Beckham isn't grinning all the time. In fact this celeb likes to keep a serious expression on her face at all times. Vogue sat down with Beckham in 2015 to ask the lady of the hour why she never shows off her pearly whites. The mother of four professed that not only does she hate that question but she is in fact smiling on the inside and believes she has a responsibility to the fashion industry not to smile. We will let you try and figure out what that means.

11. Leonardo DiCaprio

Leo used to be a carefree smiley guy but when the success of Titanic thrusted him into the limelight his world changed forever. It’s not because he has bad teeth, nor is it because he is grumpy or sad all the time. The real reason why DiCaprio keeps his lips sealed is a good one. Not wanting the paparazzi to profit from his status he has learned to keep his personal life under wraps and is prepared never to give them a shot of his perfect pearly whites. For DiCaprio it is easier to have people think he is grumpy than to give the paparazzi any more reason to snap his picture. We applaud you Leo and still think you look damn good.

10. Megan Fox

This gorgeous actress rarely cracks a smile on the red carpet or on the set of the movies she has acted in. In fact rumors have it that Megan Fox wasn't the most pleasant person to work with during the filming of the Transformers series. Fox was on The Today Show talking about her insecurities and that is perhaps why she doesn't often flash those pearly whites. Having two beautiful babies were enough to make Fox smile though and as time goes on we expect to see her flash a smile or two more often than not.

9. Kristen Stewart

Kristen Stewart knows that she rarely smiles but still won’t give them out easily. Although she is often interpreted as having a bad attitude, being grumpy and otherwise ungrateful; this simply isn’t the case for this Twilight star. When speaking to Elle about why she doesn't smile Stewart makes it clear that if she started smiling now people would be looking at her like a sellout; asking why now would she start smiling? Ex-boyfriend Robert Pattinson claims that people have decided to perceive Stewart one way and will always find a non-smiling photo to use; even if she does crack a grin.

8. Johnny Depp

For a man that has millions in his bank, a lifestyle that many dream of and; we have to wonder why this star doesn’t smile more often. Perhaps it is the fact that his whites aren't as white as he would like. It could be that Depp is the outside man in Hollywood; never fitting in to fancy galas and red carpet events; preferring now to be at home with his two kids and new wife. For a man that seemingly has everything, were pretty sure that he has a huge smile on the inside.

7. Woody Allen

This American actor, writer, director, comedian and playwright has had a successful 50 year career and one might think that a comedian should be smiling and laughing all the time. And in fact during his younger days it wasn't unusual to see him smiling on and off the stage. Not the case with Allen now though, he is rarely seen smiling on the red carpet, or at any event really. Between the controversies that surround him and the accusations that have been taking place over recent years, we understand why Woody Allen may not be smiling all the time.

6. Kayne West

This multi-millionaire has his own reasons for never smiling and whether you think he’s right or not; he does get attention for it. West chooses not to smile because it just doesn’t look cool and feels like he is smiling on the inside by not smiling on the outside. Some call him a rebel, some call him cool and some just don’t quite understand why he looks so glum. Unlike his counterpart Kim Kardashian who chooses not to smile for fear of getting wrinkles; this rapper takes inspiration from the ‘cool’ looking men from the 1800’s realism art movement.

5. Karl Lagerfield

This usually serious and reserved fashion designer hardly ever cracks a smile to compliment his signature white hair, black glasses and high starched collars. The head designer and creative director of Chanel and Fendi is serious about fashion and his cat. During an interview with the Guardian, Lagerfeld described that he is never happy with himself and that he believes he is lazy and could do more. Perhaps that is the reason we never see a smile from this fashion genius; perhaps he is too unhappy with himself. Whatever the reason is; this icon has enough reasons to smile and should do so more often.

4. Robert De Niro

If this celebrity isn't shooting the paparazzi a dirty look he is looking rather angry. De Niro was definitely more smiley in his younger days but as is the case in most of these celebs; as he gets older the smiles start disappearing. Maybe its because of the years he has endured being famous and hounded by the paparazzi, and after all this celeb does have a seriousness reputation to hold up. You can see him smiling in films such as ‘Meet the Parents’ and perhaps that is why so many people fell in love with the film. Despite the sour expression this actor is total a celebrity superstar.

3. Rooney Mara

Mara is one celebrity who refuses to smile on cue and therefore can hardly be seen photographed with a huge grin on her face. But if you dig a little deeper into this star you will soon realize that she will break into a grin every time she is genuinely happy. Telling Vogue that she refuses to fake smile and that her fake smile is downright awful, this explains why the paparazzi can only capture her sultry look. Mara admits to being insecure and shy and hates to be the center of attention. Next time you are judging her sour look you may want to think about how she is feeling inside.

2. Mary Kate and Ashley Olsen

These twins are known for their famous paparazzi pouts where they manage to show no teeth and barely smile in sync while hundreds of light bulbs flash around them. These two have a secret to these succulent pouts though and they shared it to the world. Right before they are about to pose for a picture they turn to each other and whisper prune; which relaxes their lips and forms that infamous pout. You won’t see these two reserved young women breaking out into any wide mouthed grins anytime soon; they like to keep up their signature move.

1. Uma Thurman

Uma Thurman finally revealed why she doesn't smile to Hello! magazine this year. It dates all the way back to when Thurman was just 10 years old and someone told her that she looked ugly when she smiled. Since then this actress has kept her lips tightly closed. As Uma has gotten older it seems that she allows the public and paparazzi to see more of a smile while on the red carpet, and her smile is one that is truly beautiful. Either way she suits the pouty look just as much as a wide smile.

Sources: elle.com, ranker.com, usmagazine.com, hlntv.com