Jake Gyllenhall and Josh Brolin got lost hiking in the Santa Monica mountains.
The brawny actors decided to get some practice in ahead of their appearance in climbing drama 'Everest', but things took a downward turn after they lost sight of their direction markers.
A source told the National Enquirer: "They'd started out in Malibu canyon and followed marked paths until they got to a rocky area where Jake wanted to climb. When they started back down the other side of the mountain, Jake kept insisting he knew the way but after an hour, Josh realised Jake had no clue."
Facing the prospect of darkness falling, temperatures plummeting and dangerous wildlife including lions, coyotes and poisonous snakes attacking them, the pair appealed to the first people they came across, a Boy Scout troop, who helped bring them back down safely.
'Everest' is based on the true story of two ill-fated expeditions to the summit of the world's tallest peak - located in the Nepalese Himalayan mountains - which resulted in eight people's death when they were caught in a blizzard. It is set to be directed by Baltasar Kormakur and filmed in Iceland later this year.