Why didn’t Miley Cyrus reprise ‘Guardians of the Galaxy’ role in ‘Vol. 3’? Tuesday, May 9 by ABC NewsJames Gunn has explained — albeit very briefly — why Miley Cyrus' voice wasn't heard in Galaxy of the Guardians Vol. 3.The singer and Black Mirror actress had a single line in an after-credits scene in Vol. 2 as Mainframe, an AI that in... Read More.