Friends star Matthew Perry will play a smooth-talking criminal named Benny, while Chuck's Zachary Levi is to voice a member of the Followers of the Apocalypse, according to USA Today.
The Guild's Felicia Day will voice a member of the Brotherhood of Steel, and Hellboy actor Ron Perlmen will return as the narrator, a role he has previously played in other Fallout games.
Other actors to voice characters in the game include Danny Trejo, Kris Kristofferson, Rene Auberjonois, Michael Dorn, John Doman and William Sadler.
"The voice acting provided by these actors helps drive the compelling and immersive story of Fallout and further adds to the overall gameplay experience," said Bethesda president Pete Hines.
Fallout: New Vegas will be available on Xbox 360, PlayStation 3 and PC on October 22.