Shah Rukh Khan and Katrina Kaif indulged in harmless banter during the song launch of the upcoming film 'Jab Tak Hai Jaan'. Katrina Kaif pulled Shah Rukh's leg saying that his guitar-playing in the song 'Challa' wasn't up to the mark. Shah Rukh Khan jibed back saying that neither did Katrina know the chords of her song 'Dhunki' from 'Mere Brother Ki Dulhan'.