Johnny Depp is struggling to master his horse-back stunts on the set of his latest film The Lone Ranger.
The 49-year-old actor — who recently split from the mother of his two children, Vanessa Paradis — is currently shooting the blockbuster but insiders say he has not yet got to grips with his animal co-star.
One said: "It has become a problem for Johnny. He wants to do all his own stunts, but he's been falling off his horse so often that producers worry he's going to do permanently damage his tailbone."
Depp — who plays Tonto in the upcoming blockbuster — is refusing to use a stuntman and is also growing increasingly frustrated as co-star Armie Hammer is a natural at horseriding.
The source added to National Enquirer: "He sees Armie doing everything so easily, and that's got him even more frustrated."
Depp famously swore off filming with horses after working on Tim Burton's 1999 film Sleepy Hollow, after a stunt which required him to be dragged behind two horses.
But after filming Sleepy Hollow, Depp adopted one of the film's equine stars - a one-eyed horse named Goldeneye, who was set to be destroyed after production ended.