MUMBAI — Music director and composer A R Rahman's patience was tested by Alia Bhatt who had to lent her voice for a song in her forthcoming film "Highway." The 20-year-old daughter of renowned filmmaker Mahesh Bhatt said: ""I didn't rehearse much, we went twice (to the studio). We spent quite a lot of time and Rahman sir was very patient with me for which I am truly grateful. That really stopped me from going home and screaming into the pillow," "This is the kind of experience you think you will never really have in your life. I always knew that somehow I will act, but this experience. I never really thought will happen and it did. So, if I fail as an actor, I can become a singer," Alia said at the launch of the song on Saturday. Directed by Imtiaz Ali, "Highway" hits theaters on February 21. — SG