"The movie we just did, I think, is going to be fantastic," Damon said. "It'll be out in a year or so, but I'm really, really proud of it. He gave me a huge opportunity to play a very different kind of character and it's a Terry Gilliam movie!"
Although the film is about the fairy-tale scribes, Damon says it is not a "bio-pic."
"The real Grimm brothers were these very respected scholars and important figures in German history, and we're playing them as con artists who are going from town to town and ridding it of a mill witch or bridge troll and then taking money for it from the local peasantry and then they eventually run into an actual enchanted forest," he said.
"So, it's a very funny movie, but it's got all this fairy-tale imagery. All the characters that the Brothers Grimm ended up writing about pop up throughout the movie."
Gilliam previously directed "Brazil," "Twelve Monkeys" and "Fear and Loathing in Las Vegas," while Damon can currently be seen in "Stuck On You."