The Trip comedian confirmed to The Playlist that work had begun on a script for the fictional TV and radio personality's first big screen outing, after his fellow writers agreed on a plot last July.
Commenting on the slow progress of the Partridge project, Coogan admitted: "We left it behind for a while, but we came back to it because we got a few ideas.
"We're writing it right now, going to shoot it next year. Don't know who will direct it, but Pete Baynham [Borat co-writer] and Armando Iannucci are writing it with me. We've already started it."
The faux-pas prone presenter made a one-off TV return this March for a special Red Nose Day episode of web-series Mid-Morning Matters.
Iannucci previously confirmed that the movie will be set in the character's home city of Norwich.
Watch highlights from Alan Partridge's BBC shows Knowing Me Knowing You and I'm Alan Partridge below.