As we recently told you, the funnyman gets naked once again for a full-frontal scene in his upcoming movie The Five-Year Engagement.
And Segel's costar Emily Blunt wasn't exactly jumping at the chance to see him drop trou...
"Jason was happy to get that thing out at all times," Blunt told us at the Hollywood premiere of her new movie Salmon Fishing in the Yemen. "He seems to be very willing."
Fortunately, Blunt wasn't on set for Segel's big (or little) reveal. "I didn't want to see it!" she laughed.
She may have to see it on screen, however. "I don't know if they chose the wide shot or the close up," she said. "I don't know it they're gutsy enough."
In the flick, Blunt and Segel play an engaged couple who continually put off walking down the aisle. "It's a sort of a When Harry Met Sally kind of feel," she said. "It's really great."
And as for working with Segel?
"He's such a buffoon," Blunt said lovingly. "He's my friend and he wrote it for us, and it was great because he knows my voice so he wrote it with me in mind, which is really fun."