The on-and-off "Arrested Development" film is really happening, and everyone but one cast member has already signed on. Michael Cera is still undecided on joining the rest of the TV family on big screen.

It has long been rumored that the 20-year-old actor is the one holding out the film from happening. Now, star Jason Bateman confirms that Cera hasn't committed yet.

Bateman tells eonline.com, "I know he's thinking about it. And we're all awaiting some fairly finality to all of that so Mitch can get writing."

As for the younger actor's reason, Bateman, who plays Cera's father in the show, says, "You'd have to get [Cera] on the phone to get his answer about whether he's going to come back and do it or not. He's certainly not said that he won't do it."

After toying with the idea that the movie might probably be a prequel of the TV series, creator/director Mitch Hurwitz says the film might now "pick up five years later."

No production date has been set yet.