Already this season, some of the world's biggest celebrities have gone through some pretty significant changes. Kim Kardashian got married, Jennifer Lopez broke it off with her other half and Jonah Hill turned in his picture-perfect image when he lost his cool with a paparazzo.
Still, these life changes are no match for the often unbelievable style and beauty transformations these and many other stars have made over the years. With new haircuts and hair colors, weight losses and weight gains, many celebrities have transformed from frumpy to sleek (and occasionally the other way around).
Click through the gallery below to see some of the biggest celebrity transformations over the years.
Biggest Celebrity Transformations
Celebrity makeovers and 'make unders'
Jennifer Hudson looks a lot different today than she did in her American Idol days.
Today, Jennifer looks better than ever. Here, she's rocking a sleek style in all black and a bob.
In 2007, you'd likely find Jonah Hill clad in a t-shirt and a head full of curls.
Fast-forward seven years and the acclaimed actor looks dapper with a close cut and suit.
The star initially known for her role as Hannah Montana doesn't look like a wide-eyed teen anymore.
Instead, you'll find her in a signature leotard and bleach blonde bob.
The Hills star Heidi Montag looked like this before she famously underwent plastic surgery.
Today, the reality star looks nearly unrecognizable.
Roseanne alum John Goodman didn't always look as dapper as he does today.
In 2014, the actor looks handsome and fit.
There was a time when we could only imagine Nicole Richie as a blond...
And then she boldly went a very different direction: purple! We love it!
In 2010, Rob Kardashian looked model-esque...
...but looked like a completely different person in 2013.
We're not so sure super-chic Victoria Beckham would wear this outfit and hairstyle today.
In 2014, Victoria typically opts for sleek, minimalist looks.
Ozzy Osbourne's daughter, Kelly, went dark in the '00s.
Today, the E! star brightens up a bit with a shock of blue hair and purple lip.
This goofy banged hairstyle from Jon Hamm isn't what we've come to expect from the Mad Men star.
This well-groomed but slightly scruffy look is much more like it.
The superstar has come a long way since her Destiny's Child days.
She looks ready to run the world in this style.
A young Anne Hathaway once had a lot to learn about fashion.
Now, her short hair has become iconic.
Miranda Lambert looked beautiful here in 2012, but still looks a bit different today.
Here, with a different variety of big hair, Miranda looks almost unrecognizable.
In 2009, you could have walked right past actor Joaquin Phoenix. His face was hidden behind a thick beard and often dark shades.
Today, the star rocks a clean shave and has nixed his unruly curls.
Remember when J. Lo sported dark hair? Neither did we!
Today, we can't get enough of her flowing, dirty blond locks.
Jimmy Kimmel looked like the guy next door before Jimmy Kimmel Live.
Now, he is looking spiffy as ever!
The Dawson's Creek star had girl-next-door style back in the day.
But today, she's established herself as a true fashionista, blond bob and all.
We'd be shocked to see Kim in this frilly get-up today.
Now, with her fashionisto husband Kanye West, Kim opts for something a little chicer.