I saw this documentary on the Bombay Talkie DVD released by Home Vision. Of course, HV is out of business now, so tracking down this DVD and documentary might be a bit difficult. However, the documentary is quite fun, much more so than the actual film.
The focus is on Helen, suppposedly a very famous Bollywood dancer who has appeared in hundreds and hundreds of Bollywood films. Most of these appearances were musical numbers, and a few of them are offered in this documentary. Quite a lot of fun to watch, and that's saying something, considering how I don't really like Bollywood. The documentary was made in the early 70's when Helen was still in her prime, so her interviews and the film clips go well, hand-in-hand. Check it out if you find it.