The cast also features Sanjeev Bhaskar, Eddie Izzard and Joanna Lumley, in addition to a voice cast featuring Jones, John Cleese, Terry Gilliam, Eric Idle, Michael Palin and Robin Williams.
The pic follows a disillusioned school teacher (Pegg), who suddenly finds he has the ability to do anything he wishes, a challenge bestowed on him by a group of power-crazed aliens (voiced by Cleese, Gilliam, Jones, Palin and Idle).
As he struggles to deal with these new found powers, and the events that subsequently arise, he calls on his dog Dennis (voiced by Williams) to help him along the way.
Beckinsale will play Catherine, the female lead and romantic interest to Neil.
Jones and Gavin Scotts penned the script. The film is being produced by Ben Timlett and Bill Jones at Bill & Ben Prods. Pic is set to shoot in London from March 24.
Mike Medavoy will serve as executive producer with Chris Chesser.
Worldwide sales are being handled by GFM Films.