George Clooney helped push his The Monuments Men co-star Matt Damon to lose weight for the film by ordering the wardrobe department to secretly adjust his costumes every day.

The actors filmed the movie in Germany earlier this year (13), and Clooney, who also directed the picture, has revealed his colleague was rushing to slim down for the part.

The Oscar winner decided to help out by making sure all Damon's costumes were too tight.

Clooney tells, "Matt was rushing to lose weight, and I'd have the wardrobe people take in his uniform every day, so that no matter how much he was losing, the clothes felt tight on him."