"England can take the lead on this kind of thing - letting art go back where it came from."
He added: "The Greeks are nothing but generous. They would loan it back once in a while."
Clooney asked about the Elgin Marbles at a Berlin Film Festival press conference over the weekend.
At yesterday's press conference, Clooney said it had been "one in about 100 questions at a press conference, from a Greek reporter, and I said I thought it was probably a good idea if they found their way back".
But he added: "Apparently I got in trouble for saying that and I had to do a little research to make sure I wasn't completely out of my mind.
"There are certain pieces you look at and think, 'That would perhaps be the right thing to do'.'
Clooney said he had been criticised for commenting because he was American and did not understand the situation. Matt Damon, who was also at the press conference, laughed: "That can't always be the British default setting. It's not actually an argument to say, 'He's American, he doesn't get it'."