Wiki :
On 5 January 2011, Karan Johar uploaded the first look poster of the new film on microblogging site, Twitter. The film marks the debuts of Alia Bhatt, daughter of filmmaker Mahesh Bhatt, Varun Dhawan, son of director David Dhawan, Siddharth Malhotra, ,Boman Irani's son Kayoze Irani and Kuch Kuch Hota Hai fame Sana Saeed (role of "Anjali" as daughter of Shah Rukh Khan & Rani Mukerji, in a film) .
Casting was pretty much done at a tea party at home (like in Aashiqui 2)