San Sebastian, Spain - Hollywood star Brad Pitt said on Wednesday that co-starring with a dog in his latest film, survival thriller Heart of the Beast, was "a really moving experience".
Directed by David Ayer, the film explores the deep bond between a military officer and his combat dog, Odin, who survive an air crash and become trapped in the wilderness of Alaska.
Four dogs, all from the same family, were used to portray Odin, but the bulk of the performance was delivered by a German shepherd named Uber.
"I did have a really moving experience with Uber, who plays Odin, who our dog whisperer found in New Zealand, and we bonded quickly," Pitt told a news conference at Spain's San Sebastian Film Festival, where the movie is screening out of competition.
"There were times he would do things that were just amazing, that were not in the script that you see in the film, and his expressions, they really moved me with him in the close-up," the 62-year-old Oscar winner added.
San Sebastian, the highest-profile film festival in the Spanish-speaking world, wraps up on Saturday.
A total of 17 films are vying for the top awards in the official section, with a jury presided over by director Ira Sachs.