Director Robert Luketic flew into a panic during production on his new thriller Paranoia after leading man Harrison Ford suddenly decided to shave his head bald.

Ford's co-star, Liam Hemsworth, reveals Luketic was faced with a hairy challenge five days before the Indiana Jones icon was due to report to the set to shoot his scenes.

Hemsworth says, "(Ford) did that (shaved his head) without telling anyone. We had been shooting about two weeks and then the director was on set one day and he had a really stressed look on his face and he showed me a picture of Harrison and he had a shaved head and he was freaking out.

"He was like, 'I don't know what we're going to do. We're five days from shooting with him. We're going to have to make him a wig and all this stuff.'"

Ford recently explained that he cut his hair off because he believed it better suited his character as a ruthless tech mogul, and it appears Luketic agreed - the veteran actor kept the look for the movie and Hemsworth admits he is a fan of the screen makeover.

The Australian says, "It looked good. He's Harrison Ford, so he pulls it off."