The comedy-drama movie 'Kal Ho Naa Ho' was released in 2003. The movie had Shahrukh Khan, Saif Ali Khan and Preity Zinta in the lead roles. Although Shahrukh and Saif worked together in 1993 drama 'Pehla Nasha' but 'Kal Ho Naa Ho' was their first movie where they were in lead roles together. Till then, Shahrukh had established himself as the king of romance in Bollywood and Saif too was a prominent face in the industry.
The movie depicted Shahrukh and Saif as friends and the duo won over the audience as well as critics in their roles. The movie was a superhit and did well at the box office but at some point while shooting for the movie, Saif was a bit insecure about working with SRK.
The revelation was made by Saif himself when he appeared on Karan Johar's show 'Koffee with Karan' with his daughter Sara Ali Khan. While talking to Karan, he said, "You made me insecure once. We were doing ‘Kal Ho Naa Ho’ and you said I want you to act like Shah Rukh and I said, ‘Oh no… Am I not good enough as myself.'”
The title track of the movie was shot on Shahrukh first and later when Saif arrived for his shoot, Karan asked him to act like Shahrukh. Probably this was the reason behind Saif's insecurity, because who can act like SRK other than SRK?!