George Clooney once toured 'Big Brother' house

Hollywood star George Clooney once took a tour of the US version of the "Big Brother" house, former executive producer of the reality show Allison Grodner has revealed.

The Oscar-winning actor was apparently in post-production on a film "many, many years ago" on the same studio space, when his editor who was a big fan of the show invited him along for a tour of the house.

"The peak experience of my life was giving George Clooney a tour. He was on the lot cutting a movie many, many years ago. His editor at the time was a super fan of the show.

"He called and said, 'Can I stop by and I want to bring a guest?' The guest was George. I'll admit, I went home and changed immediately," Grodner told Entertainment Weekly.

The producer said the "Catch 22" actor was unfamiliar with the reality show, but was "fascinated" with the tour.

"I have to say, he was one of the nicest celebrities I've ever met. He was really fascinated.

"Walking around behind-the-scenes was something that was intriguing to him. That was a big one. That was a highlight," Grodner said.