The 'Pretty Woman' actress praised the Hollywood heavyweight for his acting talent as well as his "gifted prankster" skills as she took to the stage to present him with the Stanley Kubrick Britannia Award for Excellence in Film prize.
Speaking at the BAFTA Los Angeles Jaguar Britannia Awards in Beverly Hills, Julia joked: "George Clooney, or as my daughter calls his, 'George Looney.' So, so honored to be here tonight. And there are two obvious reasons why I was chosen to do this.
"One, Brad Pitt was out of town. Two, Matt Damon, he's in town but he was unavailable. I consider George a friend. We have worked together in many capacities. We have acted together a few times.
"He's been my producer and my director, all of which he is immeasurably gifted at. He's handsome, he's talented, he is an exemplary humanitarian and a gifted prankster."
George, 52, was visibly moved by Julia's comments and was quick to return the compliments. The pair - who were last on-screen together nine years ago in 'Ocean's Twelve' - have recently been reunited in upcoming movie 'August: Osage County', which is co-produced by George.
The silver fox told Julia: "It has been such a pleasure to watch the woman you have become. It's very hard for me to be just straight nice because she'll get me later. But just an amazing mother, an amazing wife and a great, great friend. It's really an honour to have her here."
The old pals were seated next to each other during dinner at The Beverly Hilton Hotel, and spent the evening giggling and chatting. At one point Julia - who has three children with her husband Danny Moder - rested her head on newly-single George's shoulder, and kept a firm grip on his hand as the ceremony kicked off, but it was clear the pair were just good friends.
Other actors who were honoured at the star-studded ceremony included Sacha Baron Cohen (Charlie Chaplin Britannia Award for Excellence in Comedy), Benedict Cumberbatch (Britannia Award for British Artist of the Year) and Idris Elba (Britannia Humanitarian Award).