Joining Lupita in Monday's announcement was Games of Thrones actress Gwendoline Christie.
"I could not be more excited about Lupita and Gwendoline joining the cast of Episode VII," said Lucasfilm president Kathleen Kennedy. "It's thrilling to see this extraordinarily talented ensemble taking shape."
Lupita Nyong'o and Gwendoline Christie join the cast of Star Wars
Lupita also tweeted the news to her followers, writing: "I can finally say it out loud and proud: I'm going to a galaxy far far away!"
She added a link to an Instagram page which showed the famous Star Wars logo.
Harrison Ford, Carrie Fisher and Mark Hamill, who all became household names after the first Star Wars movie in 1977, will appear in Star Wars: Episode VII, the new film in the franchise.
Other new cast members previously announced include Girls star Adam Driver, Inside Llewyn Davis actor Oscar Isaac, Domnhall Gleeson, and British actor John Boyega. Andy Serkis, Max von Sydow, and Daisy Ridley will also star.
Casting and plot news have been top-secret for the latest Star Wars film, which will be set six years after Revenge of the Jedi.
We do now however that Episode VII will started filming at Pinewood Studios in May; it is the fifth Star Wars movie to be shot in the UK.
A picture of the new cast — including R2-D2 in a crate — was posted on the official Star Wars website when the first round of announcements were released.
A picture of the new cast was posted on starwars.com
It’s been an incredible year for Lupita, who broke out in the slavery drama 12 Years A Slave, winning her the Academy Award for Best Supporting actress.
Lupita was also named as the new face of Lancôme, following in the footsteps of stars including Kate Winslet, Julia Roberts, Penelope Cruz and Lily Collin, and has recently been rumoured to star in a new live action adaptation of The Jungle Book with Idris Elba.
British actress Gwendoline Christie currently stars in HBO's hit drama Game of Thrones and also has a role in the upcoming The Hunger Games sequel, Mockingjay.