Vidya Balan set the "Kaun Banega Crorepati 5" sets on fire when she shook a leg with megastar Amitabh Bachchan on her latest saucy number "Ooh la la" from the film "The Dirty Picture".

Big B and Vidya Balan on sets of KBC

The actress, who played a mother to Big B in "Paa", appeared as a guest participant on the show, to promote her forthcoming film.

Clad in a red sari, Vidya oozed oomph just as her character in "The Dirty Picture".

The two worked together in "Paa", where Vidya mother to Big B's character Auro, who suffers from progeria.

The episode featuring Vidya and Big B will be aired on Sony Wednesday.