According to Screen Daily The Avengers 2 is set to begin filming at Pinewood-Shepperton in early 2014, with production due to start later this year. Thor: The Dark World was mostly filmed there and Guardians of the Galaxy is set to this summer, so Marvel is happy to keep their upcoming productions at the UK studios.
Plot details for The Avengers sequel are unknown, but Joss Whedon has previously said that he would want a sequel to be “smaller. More personal. More painful. By being the next thing that should happen to these characters, and not just a rehash of what seemed to work the first time. By having a theme that is completely fresh and organic to itself.”
The villain is thought to be the Mad Titan known as Thanos, who was behind the Chitauri Earth invasion in the first film and appeared in a scene during the end credits. Nothing has been confirmed yet, however.
Robert Downey Jr. Chris Hemsworth, Chris Evans, Mark Ruffalo, Scarlett Johansson, Jeremy Renner, and Samuel L. Jackson are all expected to return and the film is scheduled to open May 1, 2015.