Doctors say gruelling shooting schedules for Ra.One may have been the cause for the injury

Shah Rukh Khan may have to skip a film award ceremony to be held later this month due to his knee injury, which is troubling him yet again.

SRK is suppose to perform at the IIFA awards and introduce the lead actor of Azaan, Sachin Joshi, son of the Gutka baron Jagdish Joshi, who SRK is very close to.

Khan, not only endorses a beverage manufactured by the Joshis, but is also going all-out to promote his son Sachin's debut. Apparently he was also instrumental in getting the popular Columbian singer Shakira for their promotional ideo.

So his plans of going to IIFA also look shaky. The source adds, "The doctor has advised Shah Rukh not to strain his knee. As a result he will have to cut down on the shooting and physical work. He may have to skip going to IIFA because of his knee injury."

Shah Rukh and Sachin Joshi remained unavailable for comment but IIFA director Sabbas Joseph says, "So far there is no change in the plan. Shah Rukh will be performing at IIFA this year."

The star had hurt his knee a year ago and was treated by the Kolkata Knight Rider's physiotherapist Andrew Leipus. But due to the rigorous shoot and tough action sequences in Ra.One his injury has aggravated.

Reportedly he will have to undergo a knee surgery next month. A source close to SRK informs, "The shoot of Ra.One has been quite challenging for SRK. He has been exerting himself quite a bit for the shoot. Consequently his knee injury has come back."