The Thor star was thrilled when he was picked to appear in Spielberg's 2011 World War II drama War Horse, but the casting meant he was going to be away on the day his closest friend was due to walk down the aisle.
Hiddleston admits he put his work first and the decision nearly cost him his friendship.
He tells Britain's Live magazine, "It was one of those crazy things where I'd said I'd be there - even if Spielberg called. And Spielberg did call and I wasn't there. We fell out really badly. It's OK now. He read me the riot act and then we went out and got slammed (drunk). Acting just demands everything and if you don't give it, there will be someone behind you who will."