Guzarish intro hum

Hey guys- I've been playing Guzarish recently while studying and I'm addicted to the sad mellow hum that the song opens with. I'm not sure if its Javed Ali or AR- I'd love to know which it is. The hum sound so familiar like I've heard it in more songs by AR but I can't seem to pinpoint any do you guys have songs with a similar sad hum that starts the song off- I'd love to give them a listen thanks a lot guys!