The song, however, is rendered in the film by Shreya Goshal and Arijit Singh, but Alia's version is titled "Samjhawan Unplugged."
The song is a remake of the song which was originally sung by Rahat Fateh Ali Khan for the Punjabi film Virsa.
Varun and Alia, who were earlier seen in Student of the Year, have once again paired up for the romantic comedy.
Talking about the film, Varun said the film was a typical romantic triangle and shot in Ambala, Chandigarh, Delhi and Mumbai.
Replying to a query, Varun said, "I have been slapped when people said there are 15 to 16 kisses in the film. I have been slapped 22 times for that."
Varun, who is playing the title role of Humpty Sharma, said he has visited Bangalore several times and really enjoyed the night times here.
"It is good to see Bangalore is having a night life till 1 am. It is fun when you sit and discuss at nights while music being played at the background," he said.
Asked when can his fans see him do an action flick, Varun said, "Yes I will do it for you soon."
Talking about the on-screen chemistry between her and Varun, Alia said she shared a love-hate relationship in reel and real life. "It is a lot like Humpty and Kavya their characters in the film.
Both stars are promoting the film in various places. Varun is playing the character of Sharma in the film who is a cricket freak and Alia as Kavya Pratap Singh, a bubbly, chatterbox character.
The film is directed by Shashank Khaitan and also stars Siddharth Shukla and Ashutosh Rana among others and is slated for release on July 11.