Promoting his upcoming action film 'Bang Bang', Hrithik Roshan has challenged Salman Khan to paint. The 40-yr-old posted on Twitter, "To the one who is more about other people than himself, Paint! And give world a message! Any. Salman Khan qubool (accept)?" Previously, Hrithik had challenged Shah Rukh Khan, Ranveer Singh, Priyanka Chopra and other Bollywood celebrities with innovative tasks.