Slideshow: Recognize This Smile?

Here comes the bride! This perfect smile was one of the highlights of a royal wedding.

Before Prince William could kiss the bride, Kate Middleton (now the Duchess of Cambridge), was rumored to have had dental work to create an improved yet natural-looking smile. "Middleton has a golden proportion smile," says Kevin Sands, DDS, a cosmetic dentist who treats celebrities in Beverly Hills. "Her four front teeth -- the ones you notice most -- are perfectly lined up. This symmetry makes for one gorgeous smile."

The first man to be named People's "sexiest man alive" twice takes little credit for the title. 

Brad Pitt reportedly once voluntarily chipped his teeth for the movie Fight Club. But women still swooned over his smile and all-around good looks. "Pitt's chiseled jaw line, defined dimples, and full lips are what make his smile so appealing and sexy," says Irwin Smigel, DDS, a New York cosmetic dentist with celebrity patients.

It’s hard to say what people talk about more: this star's movies, her family, her humanitarian work, or her lips.

Former Hollywood power couple Angelina Jolie and Brad Pitt both have famous smiles, but Jolie is known for her lips, too. "Her full, pouty lips give her a more youthful appearance," says Smigel. And she knows how to work it with dark shades of red and plum lipstick, which make her teeth appear whiter and brighter. The Oscar winner’s voluptuous lips even have their own Facebook fan page.

Before this actor could sink his teeth into his groundbreaking heartthrob role, he had to get some dental work done.

Robert Pattinson had to visit a dentist before he could take on the role of hunky vampire Edward in the Twilight movies. "The producers wanted me to have the perfect smile. I never thought anything was wrong with my teeth," Pattinson says. The actor often sports a smoldering, close-lipped smirk. "It’s a mysterious look," says Sands.

With his winning smile, this charismatic actor can light up any movie -- even when battling aliens.

Starring with Tommy Lee Jones in the Men in Black movies, Will Smith is all smiles." Smith has a warm, natural smile that matches his personality," says cosmetic dentist Catrise Austin, DDS, author of 5 Steps to the Hollywood A-List Smile. Austin says Smith's square but rounded teeth complement his square-round face. "His teeth are a natural shade of white that you [can] get from over-the-counter teeth-whitening products."

Delivered with a sexy accent, everything this sitcom star says -- and does -- is funny to her fans.

Modern Family star Sofia Vergara has an amazing red-carpet smile, says Austin. "Her teeth are perfectly lined and dazzling white" she says. Vergara says she's obsessed with proper dental hygiene. In fact, she studied dentistry before pursuing acting.

Ever since his TV days as a doctor, this star has been wooing audiences with his charming smile and dashing good looks.

Since his stint on the drama ER, George Clooney has become a top movie actor and director. But it looks like Clooney's smile has changed over the years, says Sands. Sands says Clooney probably has porcelain veneers to make his teeth longer and whiter.

This Oscar-winning actress has one of Hollywood’s most recognizable and most wanted celebrity smiles.  

What's the secret to Halle Berry's smile? She says, "A smile is pure. It's good and real, and that's sexy." In fact, so many women want Berry’s pearly whites that some web sites even sell snap-on Halle Berry veneers.

After a trip to his child's orthodontist in 2002, this top gun ended up with braces, too.

Even after braces, Tom Cruise’s smile is still not perfect, Smigel says. "His two front teeth don’t align with the middle of his nose." But the look obviously works for the movie star. "His many smile lines add charm and charisma."

Despite having one of Hollywood’s most famous smiles, this award-winning actress says it's no big deal.

"It’s always a funny little thing to talk about, my smile, because it’s just part of me like my ears or my toes," says Julia Roberts. But Austin says Roberts has the perfect girl-next-door smile. "The high lip line and exposed gums make her smile warm and inviting."

This TV host loves to talk, dance, and make people laugh.

"I'm glad I'm funny. I'm glad I make people happy, because that's very important," says Emmy-winning talk-show host Ellen DeGeneres. It’s not just her down-to-earth smile that draws people in. DeGeneres' eyes seem to laugh, too, says Sands. "There’s a hint of mischievousness in her smile and eyes that makes you feel connected to her -- like you’re in on the joke."

Brits voted this athlete as having the best smile on the field.

In a survey of the British Dental Health Foundation, Beckham topped the polls for the best smile in soccer. American fans got to see more of Beckham's great grin after he signed with the L.A. Galaxy. "What I love about his smile is that although he’s obviously taken measures to improve it by correcting the position of his teeth, his smile still remains very natural and charming," says Austin.

Angry. Surprised. Flirtatious. This supermodel says she’s perfected 275 different smiles.

"Smiles come naturally to me, but I started thinking of them as an art form at my command," Tyra Banks says. "I studied all the time. I looked at magazines, I’d practice in front of the mirror, and I’d ask photographers about the best angles. I can now pull out a smile at will."