The release of the third film in the "Bridget Jones" trilogy, "Bridget Jones's Baby" sparked discussion of Renee Zellweger and her yo-yo weight gain and rapid loss between movies. Weight loss and cosmetic surgery have left Zellweger unrecognizable from her chubby character. Cosmetic surgery also renders a wooden look and Renee needs to be very voluble and expressive in this role. Why does Renee look so different after plastic surgery? How does Zellweger lose weight so quickly and is it healthy to gain over 20 pounds to play a part? All will be revealed.

"Bridget Jones's Diary" star looks completely different

In the past few years, Renee Zellweger has had facial cosmetic surgery which has utterly changed her face. But looking at before and after pictures, it's hard to say why. Her eyes, face shape, nose, lips, mouth and even eyebrows look essentially the same. Is it the weight gain for the movies that does it? That doesn't seem to be it. Her eyes are puffier and more squinty. As "Bridget Jones" she looks younger, sweeter and more vulnerable. But it doesn't make her look like a different person--think Caitlyn Jenner or Robin Wright. Nothing is different, yet everything is different, post-surgery.

How Zellweger lost weight and why she gained it

Obviously to play a pregnant woman in "Bridget Jones's Baby" Zellweger needed to gain a little weight.

But she gained weight for "Bridget Jones: The Edge of Reason" too. However in that movie and the first one, Zellweger looked more natural. In the third film, she looks clownish as if she'd had Botox. After facial reconstruction, weight gain does look unnatural. That's what drives many Celebrities back under the knife or needle, to reshape their faces with Botox injections, nose jobs, etc.

And that makes the face look even more cartoon-like--it's a vicious cycle. There's worry about Zellweger's surgery but also her weight loss. To shed pounds, she ate nothing but a little protein and raw vegetables. There's concern too about how safe it is for actors, like Zellweger, Timothy Spall and Liam Neeson, to lose weight or gain it for movies.