MUMBAI: Shah Rukh Khan is planning a mega-budget, multi-country “Ra.One” tour in September which might also see US entertainer Akon sing the chartbuster “Chammak Challo”, while Kareena Kapoor performs to it. According to reports, it seems that Khan is planning a multi-country “Ra.One” tour in September, which will culminate in the US towards the end of the month. R&B star Akon, who has sung the “Chammak Challo” song in “Ra.One” is expected to be part of the tour.