Abigail Spencer is moving on from "Mad Men" to "Aliens."
The actress, who played Don Draper's mistress on the '60s-set AMC series, has joined the cast of DreamWorks and Universal's big-budget "Cowboys and Aliens," her studio feature debut.
Daniel Craig, Olivia Wilde, Harrison Ford and Sam Rockwell already are cast in the tale, based on a Platinum Studios graphic novel about cowboys and Indians rising up against invading aliens. Spencer will play a prostitute named Alice, a former lover of Craig's character who makes him change his ways.
"Iron Man 2" director Jon Favreau is helming the sci-fi adventure, which is shooting in Sante Fe, N.M. Universal will release the film July 29, 2011.
Steven Spielberg, Ron Howard and Brian Grazer are producing with Platinum's Scott Mitchell Rosenberg.
Spencer, repped by ICM and Untitled, also is coming off a run on the TNT series "Hawthorne."