The former 'Scrubs' beauty and current 'Mad Love' star doesn't have to go too far to recall a major turning point.

Uma Thurman muses that "every day is a defining moment."

Bret Michaels is one of the most hard-working men in show business. In addition to fronting multi-platinum hard rock icons Poison, for the past decade Michaels has also toured and recorded as a solo artist, recently even cutting a duet with Miley Cyrus.

The 'How I Met Your Mother' star found his defining moment when he went back to his high school.

Jason Derulo got into the music business as a songwriter at the age of 18, but knew from a young age that this was his path. "For me it was very early on ," Derulo tells Popeater of his defining moment as a music fan. "I was about four or five years old and I was watching television and Michael Jackson was doing a live performance. I was just flabbergasted, I was in awe of what he was doing." Derulo says it was right then he decided he would one day go on to be the top ten hitmaking singer of songs like 'Whatcha Say' and 'In My Head." "I told my mom, 'I'm gonna be just like him,'" he recalls. "And never looked back since."

For anyone who's felt the spirit of reggae, the music of Bob Marley is as seminal as the Beatles were to rock. And Wyclef Jean is not different. With both the Fugees and as a solo artist Jean's music has carried the influence of Marley so it should surprise no one that Jean credits the reggae icon with turning him onto music.

The celebrity blogger superstar says that his family keeps him healthy. What moment with them had the biggest impact?

Jason Biggs extols the virtues of marriage -- particularly his marriage, to actress Jenny Mollen.

The reality star bounces back from a down year by reflecting on what turned her around.

Watching two journeymen musicians grind it out in a bar may not seem like much of a source of inspiration, but for a young Zac Brown, the future leader of Zac Brown Band, that evening was a defining moment. “I was watching Shawn Mullins and Matthew Taylor,” he tells Spinner. "I was 14 and watching them play and sing and just sweating it out in the bar. There was probably 40 people there. It was so mesmerizing and I was ‘OK. That’s what I wanna do."

New Jersey Net Kris Humphries looked destined for greatness as a kid, but it wasn't on the basketball court. A night out with his father, though, changed everything.

'Talk' host Holly Robinson Peete remembers that her big break on a kid's classic led to some major confusion.

David Cook first caught the world's attention when he beat out fellow contestant David Archuleta for the 'American Idol' crown back in 2008. Since then, the gifted singer-songwriter has carved out a niche for himself in the pop-rock landscape with a succession of hit singles and a platinum-selling major label album. You would think that his defining moment would have been winning the American Idol title, but, as he recently told PopEater when we visited a recording session for his next album, Cook instead recalls an embarrassing tale from his youth.

The star of 'Spartacus' was able to thrive when she realized she had a full team behind her.

Frank Shamrock is a mixed martial arts icon. But the sport didn't always come easy for "The Legend."

Keyshia Cole's most significant moment came in 2006, when her reality show, 'Keyshia Cole: The Way It Is,' debuted on BET. The series -- which documented the exploits of Keyshia and her family (mainly her sister Neffe and mother Frankie) -- aired for three seasons and was a ratings hit for the network.

SlamBall star LaMonica Garrett is known for his bone-jarring hits and high-flying ways, but in high school, a surprising setback taught him a valuable lesson.

There are times when a person has to hit rock bottom to make a major change for the better in his or her life. In the case of sisters Wendy and Carnie Wilson, two-thirds of the pop group Wilson Phillips, they had to overcome personal obstacles to get to where they are now.

Just as hearing someone on a record can be a powerful moment, it’s hard to top seeing an artist belt out one of their hits onstage with more passion than can ever be put to tape. As a young teenager, Adele found that out during a life-changing concert.

First as a back-up singer for Michael Jackson, then as a solo artist herself -- Sheryl Crow's musical career has thrived over the last 17 years. So it's no surprise that she cites her defining moment as a concert, where she first "came alive."

Michael Ian Black was a founding member of MTV's classic comedy troupe The State. When he thinks back to a defining moment, of course he hears the sound of laughter.

Joe Pantoliano talks about the crippling depression that overtook him -- and the movie role that brought him out of it.

Kevin Frazier is a former anchor at Fox Sports Net and ESPN and current co-host of "The T.Ocho Show". But before he was an on-air personality he was just a cameraman living in Baltimore.

Herschel Walker has had plenty of success in the sports and business worlds, but his choice for his defining moment may surprise you.

Sometimes it takes death to make people appreciate life. In the case of the Ting Tings' singer/guitarist Katie White, it took the passing of Queen's Freddie Mercury and the famed 1992 tribute concert at Wembley Stadium for her to truly grasp what he meant to the world.

Extra host Mario Lopez found his defining moment far from the glitz of Hollywood when the Boys Club set him straight broke his troublemaking habits.

The 'Private Practice' star talks about the TV break that changed her life and the inspiration that changed her scent.

Nancy Kerrigan is a former U.S. figure skating champion and two-time Olympic medalist, but she has a hard time pinning down just which moment most defined her.

Like millions of Americans, Linkin Park vocalist and producer Mike Shinoda started out as a kid with a piano. Every week, he took lessons and learned scales, chords and melodies. At the time, he wasn't being groomed to be a superstar producer, he was just playing music. Then he got a keyboard, sampler and a four-track recorder -- and everything changed. He went from playing classical songs to tapping into the cultural zeitgeist of his own generation.

Natalie Spilger is a key player on the Chicago Red Stars defense, but her real passion is defending the environment.

Questlove's most significant music moment came at the age of 2 when, as a huge fan of 'Soul Train, he watched a young Michael Jackson do the robot in 1973 during a performance of 'Dancing Machine' on the show.

Mayim Bialik still remembers a devastating rejection when she was ten that showed her the cruel reality of Hollywood before she even made it big.

Like most music lovers, Melissa Etheridge remembers her first introduction to the Beatles. "I heard 'I Wanna Hold Your Hand,'" she tells Spinner. "I remember it just tingled me from my head to my toes."

Though he grew up in a family of actors, 'Scream' star David Arquette said he was initially turned off by the idea of joining the business. However, things changed in high school when he was approached to audition for the school play.

People born in the early ‘80s most likely grew up listening to some music that might not seem so cool today. Tegan and Sara are no different. The Quin twins revealed to Spinner that the most moving musical moment of their youth came thanks to New Kids on the Block.

Tara Lipinski won the Olympic gold medal at the 1998 Winter Olympics and claimed the title of the youngest ladies Olympic Figure Skating Champion and the youngest individual gold medalist in Winter Olympic history.

In a recent interview with the BoomBox, Fat Joe spoke about the struggles Latinos face in the rap industry. "[I'm] one of the only dudes relevant for 16 years repping the Latinos," Joe proclaimed as he proudly discussed his many achievements since bursting on the scene in the '90s.

The star of 'Deep Blue' gets his inspiration from a top talent on the hardwood floor who held the world in suspense this summer.

She may be the daughter of one the the greatest heavyweight championship boxers of all time, but Laila Ali has forged her own path to success both in and out of the ring.

Marlee Matlin talks about meeting Henry Winkler as a young child and being inspired to become an actress.

'Grey's Anatomy' star Sarah Drew looks back to the office politics of 'Mad Men' and finds her defining moments in the horrible ways women in the workplace were treated.

When Blake Shelton visited our Los Angeles studios for an AOL Music Sessions performance, his musical hero was on his mind: Garth Brooks. "I don't ever want to be a puppet up there, just going through the motions," Blake insists. "I want to actually feel it ... and [Garth] is the king of that."

Rob Reiner tells us how 'It's a Wonderful Life' inspired him to make timeless movies.