By now, most people have heard the expression "Dance like no one's watching." Well, Sir Paul McCartney obviously has ... until he realized EVERYONE was watching.
The former Beatle was enjoying Ed Sheeran's performance with John Mayer, Herbie Hancock, and Quest Love ... dancing, clapping his hands, and singing along to the music when the camera cut to him. But Sir Paul didn't realize the camera was in his face, and when he did ... he simply smiled, and sat down.
Don't stop dancing, Paul!