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Christina Aguilera - Christina Aguilera dazzles on and offstage. But she's not just a pretty face, her vocal range is also truly impressive.

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Christina Aguilera - In 2012, the stress overload of being a coach on 'The Voice' contributed to her weight gain. But she put in the work and managed to lose 49 lbs (22 kg).

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Celine Dion - The singer has always been naturally slim, but she never really looked like she had stopped eating.

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Celine Dion - Fast forward to Paris Fashion Week 2019 and Celine Dion has never looked so skinny. The singer's thin appearance worried fans all over the world.

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Vin Diesel - He was quite buff, he looked tough, he was the hottest guy in a fast car.

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Vin Diesel - But in 2015 he was spotted on a balcony with his top off and his distended stomach sparked rumors of the actor letting himself go. 

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Britney Spears - The teen sensation grew up and turned into one of the greatest names in pop music.

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Britney Spears - In 2007, the singer was reportedly struggling with anxiety and going through high levels of stress in her personal life. Images of Spears shaving her hair made headlines all over the world.

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Christian Bale - Maybe his role in 'American Psycho' helped, but Bale always had an edge to him. He looked sharp, hot, and had an irresistible bad boy vibe.

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Christian Bale - But in 2017, he looked like he could be a dad at a parent-teacher conference. The actor is no stranger to these transformations however. Bale manipulated his weight to play the protagonist in 'Vice.'

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Nelly Furtado - Nelly Furtado found success in the early 2000s, but years of touring took a toll on her mental health.

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Nelly Furtado - The singer has taken a long break and has now reappeared with a new look.

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Russell Crowe - The actor was in pretty good shape when he starred in 'Gladiator.'

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Russell Crowe - But he looks quite different now. Crowe reportedly has a troubled relationship with alcohol and does like his curry, which probably doesn't help.

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Kelly Clarkson - She was the first success story to come out of 'American Idol,' and she's still going strong to this day.

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Kelly Clarkson - But the singer's struggle with depression and eating disorders resulted in weight fluctuation throughout the years.

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Mickey Rourke - Who can forget him in '9½ Weeks?' Kim Basinger certainly didn't.

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Mickey Rourke - The actor was a boxer for many years and has had a fair share of plastic surgery, so his appearance has fluctuated quite a lot.

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Jennifer Love Hewitt - The actress was slim and had curves in all the right places. 

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Jennifer Love Hewitt - Being a mother has considerably changed how she looks today, however she still looks stunning!

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Kelly Osbourne - Ozzy and Sharon Osbourne's daughter has always struggled with substance abuse and mental health issues.

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Kelly Osbourne - Her image has changed over the years and she has struggled to keep a stable body weight. 

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Kesha - Here's the singer in 2010, when she was still known as Ke$ha.

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Kesha - The singer has opened up about her struggle with mental health issues. In this 2018 photo, the change in her appearance is quite visible.

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Matthew Perry - The 'Friends' star battled alcoholism and drug abuse for many years. 

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Matthew Perry - Chandler has changed a bit throughout the years, but he seems to be on the right track in recent years.

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Kirstie Alley - From '80s bombshell to elegant mature woman, the actress aged pretty well, we must say.

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Kirstie Alley - But Kirstie Alley confessed in an interview that she's very spontaneous, and that is why, at one point, she gained so much weight.

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Kelly McGillis - Remember her in 'Top Gun?' Yes, she was the stereotypical American bombshell everyone wanted to be with, or be like, in the '80s.

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Kelly McGillis - But unlike Tom Cruise (who's probably a vampire), the actress changed considerably throughout the years.

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Edward Furlong - Remember the kid from 'Terminator 2?' How cute was he, right?

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Edward Furlong - Here is the actor, a few years later, looking quite different from his teenage years. He too has battled alcoholism and drug addiction.

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Macaulay Culkin - Talking about cute kids from the movies, who can forget little Kevin from 'Home Alone?'

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Macaulay Culkin - He's gone through a lot since he became famous, including suing his own parents.

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Alicia Silverstone - She was the quintessential American teen with the perfect, luscious blonde hair in 'Clueless.'

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Alicia Silverstone - The actress is no longer a teenager and has changed a bit since becoming a mother.

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Rob Kardashian - Kim Kardashian's brother has not appeared much in public.

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Rob Kardashian -

Rob Kardashian gained some weight during his relationship with Blac Chyna.

See also: These celebrities now have regular jobs

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