Silambarasan aka Simbu has walked out of 'Ko', a film by cinematographer-director K V Anand, saying that he found it hard to allot more time for the movie.

"Since the story demanded a complete change in my looks, I have to wait for a long time to act in it. Hence, with a heavy heart, I have opted out of the project," he said.

Following this sudden development, sources have it that an upcoming actor, whose film is scheduled to hit screens by the end of this month, would replace Silambarasan in 'Ko'.

The title 'Ko' means king in Tamil. Tamannah was earlier tipped to be the heroine. However, yesteryear heartthrob Radha's daughter Karthika is now the leading lady of the film. The movie produced by S Kumar and R Jayaraman of RS Infotainment, who are currently producing 'Vinnaithandi Varuvaya', would be an out and out commercial entertainer, it is said.

'Ko' brings together Anand, writer-duo Subha and music composer Harris Jayaraj again after the success of 'Ayan'. Ajmal is also playing an important role.