See a new photo of Jason Segel looking skinny and showing off his dramatic weight loss for a new role in the film Sex Tape (co-starring Cameron Diaz) in Boston on Oct. 16. Credit: Splash News Online

Incredibly shrinking Jason Segel! The 33-year-old How I Met Your Mother star was spotted out in Boston on Thursday, Oct. 16, showing off his dramatic weight loss.

Though he was wearing a thick navy sweater over a shirt, Segel's skinny new frame was hard to miss. His face is also noticeably thinner, and the actor is styling darker brown hair. 

Segel is currently in Boston filming his latest movie, Sex Tape, opposite Cameron Diaz. He told Us Weekly in July that he was working on getting into shape for the film. "I've just been living healthy, exercising, eating right -- no more midnight pizzas," Segel told Us. "This time when I take my shirt off, I've made a promise to myself, it doesn't have to be funny."

"I took heat for Forgetting Sarah Marshall, where I was completely nude. But different characters require different body types," Segel explained. The actor, however, added that his latest project "is R-rated and I'm not in shape for no reason."

Tell Us: What do you think of Segel's new look?