When Hrithik Roshan jumped off a 30-foot-high clock tower in Singapore for an action shot, a cable broke in a freak accident. He fell to the ground and would likely have ended up dead or in a wheelchair had it not rained before the shot. This caused the crew to install a canopy on which he promptly fell. He was not hurt and continued shooting some minutes later. The Roshans feel his life was spared by divine intervention.
To play the role of Krrish, Hrithik Roshan lifted weights and dieted for two months to add 15 pounds of muscle to his frame. Roshan is used to shaping his body for different roles: for Koi... Mil Gaya (2003), he lost weight to look more childlike, and for Lakshya (2004), he gained weight to play the spoiled and lazy youth.
Hrithik Roshan received special training in Hong Kong for the special leap he makes in this film. Hrithik's super powers include super strength, speed, and the ability to jump superhuman distances. Like his father, objects that Krishna throws keep traveling through the air!
While performing a stunt scene on the circus set, Hrithik Roshan suffered a hamstring tear in his right leg. Doctors prescribed bed rest for two weeks, but he continued shooting after two days using painkillers. He also singed his hair while running through a fire in the same action scene.
When the film was launched, it was titled " Koi...Tumsa Nahin".