The actress told The Sunday Times that she plans to start work on a film script next year.
"I want to write Ab Fab: The Movie," she confirmed. "We'd have so much fun, and I've thought of a really nice idea.
"We thought it would be hilarious if [Edina and Patsy] went to a party on an oligarch's yacht, got drunk, fell asleep and woke up in the middle of the ocean. Everyone else has left, and the ship has been moved on."
BBC Films boss Christine Langan has confirmed to Deadline that the project will enter production once Saunders completes work on the Spice Girls London stage musical Viva Forever.
"I think she's a genius," said Langan. "I can't imagine anything more exciting than working with her."
Absolutely Fabulous will also return to television for three specials, with the first new episode airing on the BBC this Christmas.
The Killing star Sofie Gråbøl has confirmed that she will make a cameo appearance in one of the specials.
> Absolutely Fabulous returns: Thumbs up or thumbs down?
Watch a classic Absolutely Fabulous clip below: