Matt Damon, Cindy Crawford Among the Stars Attending George Clooney and Amal Alamuddin's Wedding

— -- George Clooney and Amal Alamuddin are celebrating their upcoming nuptials in Italy and they have a who's who of Hollywood A-listers to help them.

Upon arriving in Venice earlier this morning, they were photographed on a boat with their two close friends, Cindy Crawford and her husband Rande Gerber, who's said to be Clooney's best man.

Also seen in Venice: Matt Damon with his wife, Luciana Barroso, guitarist Steve Lukather, actress Ellen Barkin, and Vogue editor-in-chief Anna Wintour. Brad Pitt and Angelina Jolie are also reportedly set to attend, as are Bono and Sandra Bullock.

All the Details of George Clooney and Amal Alamuddin's Wedding Weekend

On Saturday evening, the guests will be escorted by police boats from the Cipriani hotel, where many of them are staying, to the Aman hotel for a pre-wedding party. The groom-to-be, 53, can't wait to say "I do" it seems.

"I would just like to say to my bride-to-be, Amal, that I love you very much," he said at a charity event earlier this month. "And I can't wait to be your husband."