The original ensemble is back together in the U.K. today, as Avengers: Age of Ultron begins shooting at Pinewood Studios. Robert Downey Jr., who only recently got a Twitter account, is putting his social networking skills to good use, as he continues to share photos from the set. It seems he may be gearing up to give fans one sneak peek per day. And today's photo teases an all-star cast reunion. Check out the chairs, and notice that Robert Downey Jr. seems to sit closer to the ground than the rest of his co-stars.