The Glaswegian satirist, who penned hit TV shows The Thick of It and In The Loop, is now to write and produce the first film featuring the hapless radio presenter Alan Partridge.
The news comes a day after it was revealed American broadcaster HBO had agreed to a second series of Iannucci's US sitcom, Veep.
There has been talk for more than seven years that Partridge, played by actor Steve Coogan, would be the subject of a movie and yesterday Iannucci confirmed it was finally in the works.
The film, to be directed by Father Ted director Declan Lowney, has been co-written by Coogan, Peter Baynham and Neil and Rob Gibbons.
Iannucci, who will be executive producer on the Partridge movie, told a film magazine: "It's just about all come together now, so it will be shot later in the year.
"At the moment it's The Alan Partridge Movie, but that's just a working title.
"The script is written but we're always rewriting, rewriting and rewriting."
The writer later tweeted: "Mr Alan P is going cinema surround-sound."
Lowney made the first two seasons of Father Ted, as well as the lauded special episode, A Christmassy Ted.
He has not directed an episode of I'm Alan Partridge, although he did work with Coogan on a short film featuring the characters Paul and Pauline Calf.
According to Iannucci, audiences will see Partridge on the big screen at some point in 2013.
The writer also confirmed he is working on another comedy movie.
He said: "We've written it, but it's a slapstick movie, it's not political, it's not satire."
The Partridge movie marks the biggest episode in Alan's fictional story since he started out as a clueless sports reporter on the spoof news programme The Day Today in the 1990s.
Later, the character had his own chat show, Knowing Me, Knowing You, before his fictional career declined.
Next came I'm Alan Partridge, charting his life at the Linton Travel Tavern after his wife left him and he ended up presenting the graveyard shift on Radio Norwich.
Lately, the character has featured in Mid Morning Matters with Alan Partridge, which became an online hit and was then broadcast on Red Nose Day. It transfers to Sky Atlantic this year.
Coogan recently said of the Partridge movie: "We don't see Alan, for example, getting Simon Cowell's spot on American Idol and going over there.
"That's too good for Alan. His future is always brighter in his head than it is in the real world."
Iannucci has previously stated that the Partridge movie would be based on Alan's home turf of Norfolk, rather than transporting him somewhere more exotic.
"We don't want to rush it – it's got to be right and justify itself as a film," Iannucci said.
"On the other hand, we don't want to be unfaithful to the character. We're not going mad and doing an Alan-goes-to-Hollywood thing.
"It's very much Alan in Norwich. Putting Norwich on the map. Well, somebody's map."
Iannucci is also celebrating after HBO agreed to a second season of Veep, his comedy about a powerless and neurotic US vice-president.