These stars weren't always quite as groomed and perfect as they are now. Follow their journey's from gawky youngsters to bonafide A-listers... and have a giggle along the way!
Just look at that mane! The actor can't help grinning from ear to ear in this brilliant throwback snap from his high school days. We're just glad he's been to the hairdressers since. Picture: SmoothBread/Reddit.
The comic actor is known for his brilliant and hilarious portrayals of various characters in light hearted films such as 'This Is 40', 'Role Models' and 'I Love You, Man'.
Born in 1981, Britney achieved fame at a young age. Her first studio album '…Baby One More Time', which was released in 1999, became the Best Selling Record by a Teenage Solo Artist, a title it still holds to this day. Spears' style at the time was all pigtails and a school uniforms. Quite a different look from her current one.... Picture: PA
The mother-of-two to Sean and Jayden is all blonde hair, mega-watt smile and bodycon dresses these days. Britney is still a hugely successful solo artist with a residency in Las Vegas.
Before her breakthrough performance in 'Mean Girls' in 2004, we had no idea who Rachel McAdams was. We absolutely love her goofy grin here!
Nowadays Miss McAdams is a household name, with blockbusters including 'The Notebook', 'Wedding Crashers' and 'Midnight In Paris' under her belt.
Child star Justin began his career on The Mickey Mouse Club from 1993-1995, alongside famous pals Britney Spears, Christina Aguilera and Ryan Gosling. The singer then went on to join pop band 'N Sync (definitely one of our favourite boy groups of the 90s). Thank goodness he now prefers a suit and tie to dungarees! Picture: PA
Writing pop hits is in Justin's blood, but nowadays you're more likely to see him raising the roof of stadiums for his millions of fans the world over or looking slick at an award ceremony with his gorgeous wife Jessica Biel by his side.
Unbelievably the singer actually first pursued a career in gospel music. Although our favourite pop princess didn't rise to fame until the release of her record 'I Kissed A Girl' in 2008, this awkward photo of hers was taken at the Teen Awards Artists of the Year Party in 2004. Her kohl-lined eyes and unkempt hair show a Katy who clearly hadn't figured out her distinctive style just yet! Picture: PA
These days Katy is a world class babe! The 30-year-old singer is known for her fun personality on and off the stage. Picture: PA
It's safe to say, Ryan wasn't always the dashing actor we know and love today. Back in 2005 he sported a shaved head and rather debatable patchy beard! Picture: PA
Men want to be him and women want him! What's more, the Hollywood hottie is not only enjoying an all time career high, but he's also recently become a dad for the first time to baby Esmeralda with the gorgeous actress Eva Mendes.
Another Mickey Mouse Club member, Christina had early pop success with 'Genie in a Bottle' and 'What a Girl Wants', which were both number one singles in the US. Picture: PA
By 2002 and the release of her album 'Stripped', Christina Aguilera had shed her uber-nice girl image, in favour of a more raunchy and outrageous stage persona.
We're really not sure about the dodgy crimped hair here Denise... Picture: PA
That's much better! These days Denise Richards' style has changed for a more groomed look. The former Bond girl has been working solidly has an actress and she also has two children with one of the most controversial men in showbiz, Charlie Sheen. Picture: PA
Jenny from the block has gone through quite a transformation since her younger days. J Lo's really grown into her looks nowadays and her departure from geeky starlet to showbiz queen is fully complete. The Picture: PA
There aren't many strings that Jen doesn't have to her bow. The dancer, singer, actress, fashion designer and author has recently released a pop hit and controversial video with Adriana Grande called 'Work'.
'The Parent Trap' actress was fresh faced and cute as a button at the age of 11. We love this photo of her in her gawky pre-teen days. Lohan received a Young Artist award for Best Leading Young Actress in a Feature Film, as well as nominations for Blockbuster Entertainment and YoungStar awards for her role in the classic family film. Picture: PA
The 28-year-old actress has had her fair share of troubles in recent years, but with a singing and acting career, it seems things are back on track for Miss Lohan. She is currently starring in play 'Speed The Plow' in London's West End.
Another star who found fame at a tender age, Justin Bieber was just 13-years-old when he was catapulted to worldwide fame as a child pop singer via his amazing YouTube videos. Picture: PA
All grown up at 20-years-old, the heartthrob is still melting girls' hearts the world over. The singer now has TV appearances, world tours and a string of highly successful albums under his belt. Picture: PA