The world's top-ranked tennis player and noted anti-gluten evangelist will join all the aging action stars — plus Liam Hensworth — in Expendables 2. (Deadline breathlessly reports that he is already on set in Bulgaria, even as we type.) Nole will play himself in the cameo, meaning either that Expendables 2 will involve a terrorist attack on Wimbledon or that the Expendables crew now requires a tennis impressionist among its ranks. While we're on the subject of Djokovic's extracurricular talents, allow Vulture to mention that his Twitter is pretty amusing, and if you follow for the next couple of days, you're almost certainly guaranteed a weird picture of Sly Stallone hanging out with the Bulgarian locals. Get on that!