Jason Segel and Mark Duplass discuss ‘Who Lives at Home’

An example of this improvisation, Duplass said, would be the movie’s opening monologue delivered by Jeff.

“That monologue draws a parallel between our film and the film ‘Signs’ by M. Night (Shyamalan) and so that’s the benefit of having somebody like Jason, who is also a writer and understands that structural brain,” he said. “So the take you see in the film is actually I’d say about 50 percent different from what was in the script because we kind of crafted this thing in the moment and that’s 100 percent the spirit of collaboration.”

Jeff seems to be another entry into Segel’s pantheon of memorable characters that range from Peter in “Forgetting Sarah Marshall” to Gary in “The Muppets,” along with his performance as free-spirited Sydney Fife in “I Love You, Man.” When asked what it would be like if all these characters met, Segel said he’s certain Jeff would remain pretty true to his character.

“If those characters met each other, I — you know, I never really thought about it and I think that Sydney Fife would think that my character from ‘Sarah Marshall’ was a bit of a wet blanket and I think they’d — I  think Jeff would just watch,” he said. “I think Jeff would just be watching the interaction.”

“He would be fascinated and he’d be taking notes the whole time,” Duplass said. “Yes.”

 “Jeff, Who Lives At Home” is now playing at AMC Woodlands Square 20.