A pilot for the series was taped in the spring. Production on the rest of the first season is scheduled to start Tuesday.
The show will also star Stephanie Leonidas, Tony Curran, Jaime Murray, Graham Greene, Mia Kirshner and Fionnula Flanagan.
"An unprecedented partnership between Syfy and Trion Worlds, 'Defiance' is the first-ever convergence of television and Massive Multiplayer Online gaming, featuring an interconnected world and story-lines that will co-exist throughout a scripted drama series and a multi-platform MMO shooter," a synopsis said.
Both the series and the game are to debut simultaneously in April.
The action takes place in the near future as seven unique alien races arrive on Earth and natives and newcomers must learn to co-exist peacefully.