Jason Segel Displays New Look On The Set Of 'Sex Tape'

WHOA. Is that you, Marshall Erickson?!

Yesterday, Jason Segel looked almost unrecognizable on the Boston set of his new movie "Sex Tape."

The comedy king admittedly has made an effort to shape up recently. He told Us Weekly it was all about a lifestyle change:

"I've just been living healthy, exercising, eating right -- no more midnight pizzas. This time when I take my shirt off, I've made a promise to myself, it doesn't have to be funny."

Segel will likely show some skin in his upcoming film, given its raunchy synopsis and R rating. That'd make anyone want to lose a few pounds in preparation.

Still, these photos give us cause for concern ... we hope the slender "How I Met Your Mother" star isn't taking his health to extremes.