The British actor, who starred in Arrested creator Mitch Hurwitz's recent TV show Running Wilde, told Splitsider that he was "too nervous" to ask Hurwitz who he'll be playing in the Fox sitcom's movie spinoff.
"Mitch told me is that he's writing me into the Arrested Development movie, which I'm super excited about," he said.
"It's all properly happening. I don't know anything about it other than that he's writing it and it's happening and I'm going to be in it, apparently."
Serafinowicz has also appeared in Shaun Of The Dead, Couples Retreat and BBC sketch comedy The Peter Serafinowicz Show.
Hurwitz recently told DS that he hopes to have the Arrested Development movie in cinemas this year.
> Click here to read our interview with Mitch Hurwitz and Will Arnett