Imran Khan has just wrapped up his favourite song from his upcoming film, Katti Batti. Sau aansu roye do akhiyan comes towards the climax, after his character, Maddy, breaks up with his live-in partner, Payal, played by Kangana Ranaut. "His heart is shattered, but he's not ready to let go. This comes through in the line, Dil ka musafir baat na mane, mud mud dekhe raste purane, zidd chodta hi nahin," Imran points out, adding that it was easy to connect with the script-the fights, the making ups and even the break-up-since he and his wife Avantika have been through it all for 13 years now. "Actually, anyone who is in a relationship will understand what Maddy is going through."

He's in pain because he has no idea why Payal has left him and where she has gone. Even his friends, who had brought them together, are now behaving as if she was the worst thing that happened to him. "Around this time, Maddy chances upon a rock band in Delhi called Foslas--Frustrated One Sided Lovers Associationwho sing this song which mirrors his feelings perfectly," explains director Nikhil Advani, who told his trio of composers, Shankar-Ehsaan-Loy, that he wanted a Def Leppard and Whitesnake kind of a love song.

They obliged in a day. "After doing seven films together they know exactly know what I want," admits Nikhil.

The song started in Ahmedabad and concluded on Tuesday in a suburban studio in Mumbai. Nikhil didn't want a choreographer as it's an intimate number. "I wanted both Imran and Kangana to be really comfortable with each other and for the audience to feel their chemistry. When I signed them, I was told they are an odd pair. Today, when you see them on screen, they're picture perfect," he smiles.