PHOTOSTilda Swinton’s Dramatic Transformation for New Role—Plus 6 More Celebs Who Made a Drastic Change for a Movie

Renée Zellweger in ‘Bridget Jones’s Diary’

Who could forget Renée Zellweger in Bridget Jones's Diary?!

To play the star of the film, the 47-year-old actress gained a reported 30 pounds, which she obtained by going on a 4,000 calorie-a-day diet eating high-calorie, high-fat foods, such as donuts and pizza.

Nowadays, the actress is sporting a slimmer figure and was even criticized last year for appearing to have an eating disorder. She, of course, slammed those rumors saying they were "unfair and disappointing."