The 'Momuments Men' actor is "really excited" his close friend is to marry Amal Alamuddin and though his pal has previously vowed never to tie the knot again, Matt insists he wasn't shocked by the news.
He told People: "Anyone who has met Amal isn't surprised, and we're all really excited for him."
The 43-year-old star is thrilled George - who was married to actress Talia Balsam from 1989 to 1993 - has found lasting happiness with the human rights lawyer.
He told Closer Weekly magazine: "I'm just thrilled that he met Amal and that they're as happy as they are. He deserves it."
However, Matt - who raises stepdaughter Alexia, 15, and daughters Isabella, seven, Gia, five, and three-year-old Stella with wife Luciana Barroso - insisted he doesn't know if his 53-year-old pal has any plans to start a family with his wife-to-be.
He said: "You gotta ask him that one. I don't know."
George's father Nick recently spoke of his happiness that his son is getting married again.
He said: "We are thrilled. We have had an opportunity to interact with this wonderful young woman and these are two great people.
"We are thrilled at their decision and we hope for them the best."