The cast of 'Marvel Avengers Assemble', from left to right, Mark Ruffalo, Tom Hiddleston, Robert Downey Jr, Jeremy Renner, Scarlett Johansson, Cobie Smulders, Chris Hemsworth and Clark Gregg, assemble for a group photograph ahead of the European Premiere of the film at a west London cinema, Thursday, April 19, 2012. (AP Photo/Joel Ryan)