The tidbit was first tweeted out by blogger Sarah Ruhlman, who was at the Los Angeles press junket for the movie.
In an interview with The Huffington Post, actor Dave Bautista, who plays Drax, confirmed Cyrus has role in the film, saying, "I heard that she's uncredited and a voice somewhere." He couldn't remember the details but added, "I know I've heard that."
According to Ruhlman's tweet, Cyrus is the voice of Mainframe. In the comics, Mainframe is an evolved technology that's actually an alternative version of Vision. DenOfGeek explains Mainframe's history:
Speaking of classic Avengers in the future, Mainframe was actually the Vision, the beloved Avengers synthoid who is about to make his film debut in next year's Avengers sequel. In the Guardians future, the Vision had evolved to make up the operating system of an entire planet. Calling himself Mainframe, this hero from the past was tasked with protecting the shield of Captain America and later joined the Galactic Guardians.
If Cyrus is in fact Mainframe, it solves a little mystery from the "Guardians of the Galaxy: Vol. 2" press conference on Thursday, when Marvel boss Kevin Feige and director James Gunn reportedly teased the role. As ScreenRant recaps:
Kevin Feige: Have you told anyone who Mainframe is?
James Gunn: I haven't told anyone, yeah. Should we?
James Gunn: Oh I think I actually did. I blew it. I told one person.
Kevin Feige: It'll get out.
Well, now it looks like it's out. And it's a party in the gal-ax-ay!
"Guardians of the Galaxy: Vol. 2" hits theaters May 5.