When James Cameron finds someone he wants to work with, he holds onto that, regardless of how long it takes him to find a role that suits that person. The evidence for that is in the latest casting for his Avatar, where Cameron has just added Stephen Lang and Michelle Rodriguez to his cast, which already included Sigourney Weaver and Wes Studi.

Lang (Gods and Generals) will play a Marine Corps colonel who takes charge of the troops on Avatar’s distant planet. It’s a role that’s been twenty years in the casting. Lang and Cameron first met over a role in Aliens that Lang didn’t get, but Cameron remembered the actor for Avatar.

Michelle Rodriguez will play an ex-Marine pilot. No doubt she’ll be gruff and tough. Cameron hasn’t been waiting quite as long to work with the “Lost” actress. He told Variety he had been wanting to work with the actress since he saw Girlfight seven years ago.

Avatar has entered into production in L.A., although the majority of the production will take place in New Zealand when the company moves to Weta Digital’s soundstages in October.