Charlize Theron is ''devastated'' at having to shave her hair off again.

The 38-year-old actress has been ordered to chop her locks off for the second time - just as her boy crop was finally growing out - in order to film re-shoots of certain scenes for her forthcoming movie 'Mad Max 4: Fury Road'.

The South African-born star will have to return to Namibia with her co-stars Tom Hardy and Rosie Huntington-Whiteley to reprise her role as Imperator Furiosa in the post-apocalyptic action flick.

A source told the Daily Mirror newspaper: ''Charlize really didn't love having a crew cut and was thrilled when it eventually started growing out. It's now at a great, workable length and she has been proud to show it off.

''However, early audience tests showed cinema-goers weren't too impressed with a few scenes, so the director and writers have re-grouped and made some important changes. Naturally they want everything to be perfect as it's a big-budget movie,

''Charlize is obviously contractually obliged to go along with any re-workings of the film, and will soon be shaving off her hair once again. She is devastated. It also means a few more gruelling workouts to rehab the athletic physique she had over a year ago.''

The news came as a surprise since filming for 'Mad Max 4' originally wrapped last December.

The original 1979 movie, famed for launching Mel Gibson's career, was criticised at the time for its graphic scenes of violence.