Aditya Chopra is at the moment completely immersed in getting his father film ‘Jab Tak Hai Jaan’, doyen Yash Chopra’s swan song, ready.

With one-and-a-half months to go before the film’s Diwali release, Adi now flies to Switzerland to shoot a romantic song featuring Shah Rukh Khan and Katrina Kaif.

The song, we hear, would be as intensely romantic as ‘Mere dil mein aaj kya hai’ from Yash Chopra’s Daag, the first film the senior Chopra directed for his home banner Yashraj Films in 1973.

Says a source close, “When the situation for the romantic song was conceived Yashji and Adi gave the great Sahir Ludhianvi’s lines ‘Mere dil mein aaj kya hai tu kahe to main bataa doon’ from Daag as a reference. Now the song will be shot in the snowfall capturing the same desperate romance between Shah Rukh and Katrina Kaif that Rajesh Khanna and Sharmila Tagore projected in Daag.”

“It’s like a tribute to Rajesh Khanna,” says the source.

The same source adds that this song apart, Jab Taak Hai Jaan bears no resemblance to Daag in content.