Rose Byrne will star in 'X-Men: Apocalypse'.
The 35-year-old actress will reprise her role as CIA agent Moira MacTaggert in the latest instalment of the superhero film.
Screenwriter Simon Kinberg revealed: "She's a significant character in the movie.
"We ended First Class with Charles [Xavier] having wiped portions of her memory of her experience with the X-Men. They are, essentially, strangers to her when she meets them.
"It's certainly a rich relationship that we started to dig into in First Class, and would like to mine more in this one."
The movie's fans can also expect "closure" at the end of the film for some of the lead characters.
He said: "This movie is the completion of the first arcs of Charles, Eric, Raven, and Hank, who are essentially our main characters.
"They're such young actors and young characters, so there's a lot more story to tell. But as a first phase of their lives, there is this feeling of closure by the end of the movie."
'X-Men: Apocalypse' will be set in the 1980s, with the decade's music and fashion trends in line to be included in the film.
Simon added to EntertainmentWeekly: "That's the era that I grew up in.
"The music, the fashion, the video games: We really want to integrate all of that in the movie, and have it infuse the movie with a different vibe."
Jennifer Lawrence, Channing Tatum, Michael Fassbender, Nicholas Hoult and James McAvoy have been confirmed for the latest instalment.