Michael Fassbender was in a joking mood last night following his London premiere of A Dangerous Method! Inside 34 restaurant, he danced around with a Burberry Prorsum-clad Keira Knightley and their costar Viggo, as well as some other lucky attendees! Michael then sat at a piano to serenade the group that also included Keira's mom Sharman Macdonald. He got a piggyback ride from a friend out to his car, then proceeded to mock-fight with a group of photographers. Keira made a more low-key exit with her Klaxons musician boyfriend James Righton. It was an evening of fun during what's shaping up to be another busy year for Michael. It was recently confirmed that he'll work on another X-Men movie with director Matthew Vaughn.