Ashton Kutcher pulled over to repair a stranded hiker's car on Saturday night.
The 'Dude, Where's My Car?' star, whose fiancée Mila Kunis is pregnant with their first child, came to the aid of a group of hikers after their car broke down in the Hollywood Hills in Los Angeles.
The driver told gossip website TMZ.com that his battery died while they were hiking, so they pushed it to a nearby street and began flagging down other cars in a bid to get someone to help them jump-start their vehicle.
A member of the group captured a video of the road-side rescue, during which Ashton can be heard laughing and says: "I've never f****ing not been able to find a battery in a car."
The group were stunned when the 36-year-old actor spotted them and pulled over, offering to help.
Ashton told them that he had to drop his passenger, believed to have been 'Black Swan' star Mila, at home first, but quickly returned to the scene to assist them.
The source said that the actor initially struggled to find his own battery, because it was located in the back of his Lexus, but eventually helped them get back on the road.