Hollywood's reigning prankster did not disappoint Thursday when he snuck up behind Steven Spielberg, Jerry Seinfeld and Seinfeld's wife, Jessica, for a funny photobomb at the USC Shoah Foundation gala at New York City's American Museum of Natural History.
Clooney, 52, peeks above the clueless trio, raising his hand and eyebrows in mock alarm.
The amusing photo added some levity to the event, where Clooney received the Ambassador for Humanity Award for his work raising awareness on the genocide in Darfur and for cofounding the Not on Our Watch project (with celebs including Brad Pitt and Matt Damon), which seeks to prevent further atrocities.
"George is the best kind of humanitarian," Spielberg said while presenting the actor with the award. "He is a humble humanitarian."
Clooney's longtime friend and Gravity costar, Sandra Bullock – another recent victim of one of his pranks – also spoke at the event on behalf of her pal, praising him for the childlike optimism he brings to his humanitarian passion projects.
Yet she couldn't help needling him as well, referring to him at one point as "a child."
One look a this playful photobomb makes it clear why.