The film features the voices of Reese Witherspoon , Seth Rogen , Hugh Laurie , Will Arnett , Kiefer Sutherland , Rainn Wilson , Stephen Colbert , and Paul Rudd .
`` Monsters vs. Aliens '' has the voices of Reese Witherspoon , Seth Rogen , Hugh Laurie , Will Arnett , Conrad Vernon , Rainn Wilson , Kiefer Sutherland , Stephen Colbert , and Paul Rudd .