Ketan Mehta's The Rising starts production in Mumbai next week, with Britain's Prince Charles lined up to snap the clapperboard to mark the start of principal photography. Prince Charles is currently on a nine-day visit to India.

Costing $20m, The Rising is set to be the most expensive film ever to be produced in India.

The India/UK production is based on the life of Mangal Pandey, India's first known revolutionary freedom fighter, who was hanged by the British in 1857 for revolting against their rule. The film is being shot in both Hindi and English language versions.

The film stars Aamir Khan, Rani Mukherjea, Aishwariya Rai and British actor Toby Stephens.

The Rising is backed by the UK's Capitol Pictures, and is produced by Manmohan Shetty's Entertainment One, Bobby Bedi's Kaleidoscope Films and Ketan Mehta's Maya Movies.

Mehta told that he has been working on the film for the past five years. "The project is getting bigger with each passing day," Mehta added, "It will be the most expensive Indian film ever produced."

Meanwhile lead actor Aamir Khan, who has not appeared in any Hindi films for the past two years, is getting back into shape for his role. He has been working out regularly in a bid to shed the extra kilos he has put on since last starring in a film.

He has also been reading every major book on revolutionary leader Mangal Pandey.

He has also spent time with soldiers of the Indian army posted on the frontline to prepare for the role.