Brad Pitt is keeping the surprises coming during his promotional trail for new zombie movie World War Z by turning up unannounced at a second screening of the film on Saturday (01Jun13). The Hollywood hunk, who plays a United Nations employee interviewing survivors of a zombie outbreak in the blockbuster, stunned filmgoers at a preview of the movie at the Empire Leicester Square in London, where the world premiere of the film is set to take place on Sunday evening (02Jun13). Standing in front of the cinema screen in the packed theatre, he told the crowd, "This has been a long-time coming - this film. I think we've got something original. 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." This is the second screening Pitt has made a surprise appearance at - he delighted fans at a cinema in New Jersey last month (May13) and handed out T-shirts to the thrilled crowd. Pitt is expected to be joined on the red carpet on Sunday night by his fiancee, Angelina Jolie, marking her big return to the spotlight since revealing her double mastectomy secret to fans last month (May13).