Actress Alia Bhatt, who is playing one of the leading ladies in the upcoming film "Kalank", visited Mumbai's iconic Gaiety theatre for the first time in her life. Varun and Alia also stepped on the theatre's roof and wooed the crowd by grooving on their just launched song "First class". The song also features Aditya Roy Kapur, Madhuri Dixit Nene and Kiara Advani. Composed by Pritam and written by Amitabh Bhattacharya, it is sung by Arijit Singh and Neeti Mohan.