And it's already making waves. And not just because Shah Rukh Khan takes to the streets of London - a guitar in hand and a happy smile on his face - to sing the song!
Sung by Rabbi Shergill, Challa is catchy, with the true-blue Punjabi flavour the singer is renowned for.
But we do feel that Rabbi's voice doesn't suit SRK too well. However, we are willing to overlook that to listen to A R Rahman's music and Gulzar's lyrics.
And is it just us or is Challa very reminiscent of Bulla ki jaana? Check out the song and let us know in the Comments slot below!
Watch SRK bring Challa alive: