One of young Hollywood's brightest stars and biggest talents, Stewart has become famous around the world since landing her break-out role as Bella Swan in the hugely popular Twilight franchise.
Born into a showbiz family, Stewart dreamed of becoming a writer or director, but her debut playing Jodie Foster's daughter in 2002 film Panic Room put her firmly on the path to stardom.
In between her Twilight outings, Stewart has played a stripper and a rock star, added a haul of trophies to her mantel and kept fans guessing over her rumoured romance with co-star Robert Pattinson.
To celebrate her 21st birthday, WENN has uncovered 10 facts about Stewart that may have passed you by:
- Stewart was born in Los Angeles but is actually half-Australian - her mum originally hails from Maroochydore in Queensland.
- The actress has a musical side - she wrote the track Tracy's Song for her movie Into The Wild and can be heard singing it on the soundtrack.
- Her part in Panic Room originally belonged to Hayden Panettiere. The film was recast when Nicole Kidman was forced to pull out of the lead role due to an injury sustained filming Moulin Rouge!
- She has amassed a reported $25 million (£16.7 million) fortune from her role in the vampire saga.
- Stewart struck up a friendship with Joan Jett to play the rocker in last year's (10) The Runaways biopic, about the 1970s all-girl band.
- She shares her birthday with Dennis Quaid, who played her dad in Cold Creek Manor, as well as Sex and the City star Cynthia Nixon and Playboy boss Hugh Hefner.
- She traded vamps for tramps in her saucy movie Welcome to the Rileys, in which she played a young lap dancer who offers to service The Sopranos star James Gandolfini.
- She and Pattinson have repeatedly refused to confirm reports of a romance but they've fuelled speculation by ringing in both 2010 and 2011 in Britain's Isle of Wight.
- Fans love Pattinson and Stewart's onscreen chemistry - the couple has taken home the Best Kiss trophy at the MTV Movie Awards twice.
- Stewart counts her Twilight co-stars Nikki Reed and Dakota Fanning among her closest friends.