George Clooney may be an A-list actor, but that doesn't mean he can't enjoy a good prank.
The "Gravity" star was evidently feeling silly at the USC Shoah Foundation gala at New York's American Museum of Natural History Thursday, and snuck up behind Steven Spielberg, Jerry Seinfeld and Jessica Seinfeld while the trio unknowingly posed for a picture.
Despite the lighthearted moment, Clooney was not being honored for his sense of humor, but for his humanitarian work. Spielberg presented him with an Ambassador for Humanity Award, calling him "an unparalleled example of action over apathy."
For more celebrity photobombs, browse the gallery below.