Lupita Nyong'o joins 'Star Wars' cast

This AP file photo taken on May 15 shows Lupita Nyong'o at the IFP and Calvin Klein Women In Film Party at the 67th international film festival, Cannes, southern France.

Three months after winning an Oscar, Lupita Nyong'o is going to a galaxy far, far away.

The Walt Disney Co. announced Monday that Nyong'o is joining the cast of "Star Wars: Episode VII." The 31-year-old actress became a breakthrough star for her award-winning performance in "12 Years a Slave."

Also added to the cast was Gwendoline Christie, best known for playing the hulking Brienne of Tarth on HBO's "Game of Thrones."

When the principal cast of "Episode VII" was announced last month, the lack of women raised some eyebrows. Nyong'o and Christie join an ensemble that includes John Boyega, Daisy Ridley, Adam Driver, Oscar Isaac and Andy Serkis.

Production is underway for the movie, which is being directed by JJ Abrams. It's slated to open in December 2015.