The Times of India reported on its Web site this week that the Bollywood superstar has lost more than 10 kg (approximately 22 pounds) in three days for her new film "Dhoom 2," which is due for release in India this fall.
Rai, 32, who is often called one of the most beautiful women in the world, was asked to gain weight several months ago for another role by "Guru" director Mani Ratnam, the paper reports.
To shed those pounds, fitness guru Deepika Mehta was called upon to design a training program for the actress when she began shooting "Dhoom 2" in Namibia four months ago.
Rumor has it the "Dhoom's" producer, Aditya Chopra, wanted Rai to exude sensuality in the film and that she may even wear a bikini in some scenes, the paper reports.
Now Rai wakes up at 4 a.m. every morning, undergoes a two-hour workout with Mehta, and then heads for the movie set, the Times said.
"She has been working 16 hours a day for the film and is exhausted by the end of the day," a source said.
"Ash is a very dedicated actress and she is working hard to get under the skin of her role. She will be back by the end of this month," Hari Singh, the actresses' business manager and spokesperson told the paper.
By Amy Bonawitz