Jennifer Lawrence's 'Hunger Games' hair cost £18,000.

The 21-year-old actress went from blonde to brunette to play heroine Katniss Everdeen in the new movie, but had wigs of various shades of brown brought in as she was reportedly reluctant to let stylists experiment with her actual hair.

Linda Flowers, Head Hair Designer for film - which is based on Suzanne Collins' book trilogy - told BellaSugar: ''I rented £18,000 of hair of all different shades of brown, from light brown to brown with a little bit of red in it.

''It made Jennifer comfortable that we weren't going to experiment with her colour.''

Once the final colour was selected, Jennifer then allowed her hair to be dyed to increase her resemblance the Katniss described in the novel.

Meanwhile her conditioning coach Joe Horrigan has revealed how he helped transform her body into that of the 16-year-old hunter.

He told MTV News: ''Jennifer and [director] Gary Ross had discussed how they felt that she should look, they thought that she should be a little bit leaner - it is, after all, entitled 'The Hunger Games' - but she shouldn't be gaunt.

''She worked with me usually twice a day, and that could be a combination of work at the track, which included agility drills, sprint work and running work, and she also had to work with an archery coach three or four days a week, and in the evening we would do stationary bike work, a mix of anaerobic and aerobic work.

''At a certain point she had to start working with the stunt crew. They had their own obstacle course and wanted her to be able to hop over trees and climb trees and that type of thing, so she was very familiar with it.

''Everything just came together and we all felt that over a period of time she became Katniss.''