The 'Anchorman 2' actor is expected to take the lead role of Henry 'Hank' Pym, aka Ant-Man, in the superhero movie, according to Deadline.
Rudd was previously rumoured to be a frontrunner for the lead role in the blockbuster - which will be directed by 'The World's End' director Edgar Wright - but faced competition from 'The Dark Knight Rises' star Joseph Gordon-Levitt.
The actor is still linked to the film and he could be cast as thief Scott Lang who steals Pym's technology to become a new Ant-Man.
The movie will be part of Marvel's 'Phase 3' storylines, following the release of 'The Avengers: Age of Ultron' in May 2015.
It's likely Rudd will also join the third 'Avengers' movie, starring alongside Robert Downey Jr (Iron Man), Chris Hemsworth (Thor), Chris Evans (Captain America) and Mark Ruffalo (The Hulk).
Marvel Studios boss Kevin Feige recently described 'Ant-Man' as a 'heist movie' and the cast are expected to be announced before the end of the year.
