It was recently announced that Judd Apatow is to produce the film about the character created by Reubens in the '80s on his show Pee-Wee's Playhouse.
Reubens has told Collider that he has finished rewrites on the script for the movie, and the film should start shooting any moment.
The actor said, "It's getting shot very soon. I actually wasn't supposed to talk about it, initially. So, it got leaked about six months to a year before it was supposed to. I've been warned not to talk about any of my new projects, but that I can talk about because I blew it and it's out. It's even on IMDB now. So, that's supposedly any minute."
The 1986 feature film Pee-wee's Big Adventure launched the Pee-Wee character to international success.
Reubens has since starred in several television specials based on the character, as well as a recent Broadway show.
Watch a clip from Pee-wee's Big Adventure below: