Speaking at the Guardians Of The Galaxy Vol. 2 premiere, the actress, who plays Gamora, talked about the involvement of Guardians stars in the Avengers films.
Asked about the third Avengers film on Monday, she said: "I think the Guardians just shot their part when it comes to Infinity War.
"And we all have to go back for Gauntlet later this year."
But later on Tuesday, James Gunn, writer and director of the Guardians of the Galaxy franchise, denied Saldana had given the game away.