Entertainment Tonight

Brad Pitt made a surprise appearance at the first screening of "World War Z" Saturday in London, ahead of the film's highly anticipated premiere Sunday.

"This has been a long-time coming - this film. I think we've got something original," Pitt said, thanking the media who flew in from around the world. "I think we've got something genre-bending. I think we've got something terribly realistic for summer fair. I'll let you guys decide."

Also on ET: Brad Pitt's Hottest Pics

World War Z, based on the novel by Max Brooks, stars Pitt as a United Nations employee who must find a way to stop the pandemic that's defeating armies and collapsing governments. The film hits theaters June 21.

Angelina Jolie is rumored to be making her first appearance since announcing she underwent a double mastectomy at Sunday's London premiere. 

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