The Night at the Museum star rose to fame with his U.K. series about a failed radio and TV presenter, before moving on to Hollywood films including Tropic Thunder and Around the World in 80 Days.
Earlier this year (10), Coogan revealed he is keen to reprise his breakthrough role for a movie - but only if he and fellow writers Armando Iannucci and Peter Baynham can come up with a good enough story.
Now the project is edging closer to reality - Coogan and Iannucci have decided on a plotline for the film.
In a message on his Twitter.com page, Iannucci writes: "And the Partridge news is that we've now agreed a story for the film. It's NOT Alan goes to America."