Check out photos of Jennifer Lawrence, Rebel Wilson, Aaron Paul, Kelly Clarkson and other epic celebrity photobombs
Emma Thompson stood behind an unsuspecting Lupita Nyong'o at the 2014 SAG Awards on Jan. 18. "I only learned [about it] afterwards," the 12 Years a Slave star told Jimmy Fallon. "Someone sent me the GIF, and I was just like, 'Oh my God.' I had no idea she was doing that."