The making of Waqt 1965
https://www.youtube.com/watch?v=xAZi7AGDfA4
Looking at this short: the making of waqt, we can see where at 123/124 the name of Erica Lal name was mentioned: at 408 she sang Aage Bhi Jaane Na Tu
So that means Erica Lal was the lady who lip sync that gem from Asha Bhosle