Yash Raj Films launched Jab Tak Hai Jaan's first song Challa featuring Shahrukh Khan on Monday and within few hours of its release the song got 25,000 hits.

In 'Challa' song, Shahrukh Khan is roaming in the streets of London and he suddenly bumps intoKatrina Kaif for the first time. Talking about this songShahrukh Khan posted on Twitter, "Challa will be out on the Oct 1 (Monday). Looking forward to it, haven't seen it since we finished shooting it."

The song is sung by famous Sufi singer Rabbi Shergil (Bhulla Ki Jaane fame). 'Challa' song too has a Sufi touch in it. The music of Jab Tak Hai Jaan is composed by Oscar winner AR Rahman.

Jab Tak Hai Jaan is Yash Chopra's last film as a director. The director revealed on his 80th birthday that Challa is his favourite song from Jab Tak Hai Jaan. Yash Chopra also confirmed that he will very soon shoot his signature white saree song ,where Katrina Kaif will be wearing a white saree in Swiss Alps.