The actor can currently be seen in the spy thriller Agent Vinod, which co-stars his real-life girlfriend Kareena Kapoor.
He told Mumbai Mirror: "When I was younger I wanted to be a cricketer as well. I used to play cricket in Pataudi. We had a lovely childhood. We learnt how to shoot game.
"However, I never had too many friends back there. At times it got boring. I had a friend, the sweeper's son Mukesh.
"He would imitate Amitabh Bachchan and I wanted to be more like him."
The star added: "The turning point [of my career] came with Kal Ho Na Ho and Hum Tum. In Kal Ho Na Ho, I was the parallel lead.
"It was a big budget Dharma production. Big money. Big hit. Seeing that, Aditya [Chopra] asked me to do a solo film Hum Tum.
"It became a hit. Finally Saif had that one solo hit that every newspaper despite good reviews would always write about in the footnote."
Khan revealed this week that he had found putting music into the film difficult because he thought singing as a spy was inappropriate.
He has also described dancing on screen as very "liberating".