Doom sequel already in the works?

The Doom movie is not coming out until this Friday, and yet key cast members have already signed on to do a sequel (assuming enough people are curious enough to see the first film). Karl Urban and Rosamund Pike, who play siblings in the upcoming movie, have signed for potential sequels to the videogame-to-film franchise.

Dwayne "The Rock" Johnson has not committed to coming back for a 2nd outing, but is interested "and it's possible [he could come back]," according to the man, himself.

Reviews of Doom have been hard to come by so far, but should be hitting the net in the next few days. Will Doom earn the required funds for the studio to greenlight a sequel? 

[via 1up]