Imagine that Stag party... If George doesn't end up naked, strapped to either an inflatable version of himself or that horrendous picture he made Richard Kind hang in his gaf for years, while floating down a very public waterway, someone hasn't done his job right. To put it another way - no pressure, Matt Damon. Yep, he went for Matt, not Brad.

The 53-year-old star proposed to his girlfriend Amal Alamuddin last month and although rumours had suggested he was planning to ask Brad Pitt to be his best man, it's now been revealed that he's chosen his Monuments Men co-star instead.

A source with a big stirring stick told The Sun: "A lot of people thought Brad was a certainty to be George's best man as they have been such good friends for years. But he is probably even closer to Matt. Besides many years ago, during one drunken night together, George made a promise to Matt that he would make him his best man if he ever got married - so Matt called to claim his prize."

However, as 50-year-old Brad worked with Matt, 43, and George on Ocean's Eleven and it's (unfortunate) sequels, it's thought that the hunk will be part of the bridal party in some capacity.

The source added: "Brad took the news with good grace - but he did say he'd heckle Matt during his speech."

Meanwhile, George is reportedly planning to throw his British lawyer fiancée the wedding of her dreams either at his home in Lake Como, Italy or Cabo San Lucas in Mexico, before relocating to London so that she can continue her work as a barrister at the Doughty Street Chambers.