When Rani Mukherjee lives in Paris, there is a scene in which her mother is watching Teesri Manzil. It's the scene in which Rani is reading and Saif calls her for lunch.
Instrumental version of "O Haseena Zulfon wali" is incorporated into the song "Aankhen Khuli Ho" and Helen even dances to the music just as she did in the original.