Actor Kunal Nayyar, who has been with American TV show “The Big Bang Theory” since the beginning, says he will be associated with it for as long as possible."We could all have walking sticks doing 'The Big Bang Theory' season 20. I think realistically there's less time left now than there was on the show before. Maybe it will go to 11, 12 or 13. I will do it as long as I can. But I think it is somewhere in that range,” Bang showbiz magazine quoted Nayyar as saying, reports femalefirst.co.uk.The 34-year-old has essayed the role of Rajesh Koothrappali in the show since 2007, with actors Johnny Galecki, Jim Parsons, Kaley Cuoco and Simon Helberg."We have one more series in our contract, that's season 10. Other than that I don't know. But I'll keep doing it for as long as they will have me,” the actor added.