Director Sajid Khan recently shot a special song with Akshay Kumar and 20 top Bollywood actresses for his upcoming film "Hey Baby", but sources say there is yet another surprise element.

This mega budget extravaganza by producer Sajid Nadiadwala is to feature a special superstar as well. "A top star will make a very interesting special appearance in the film," said an informed source.

When contacted, Nadiadwala said: "I'm not revealing much at this point of time. Just wait and watch."

According to trade speculation, it could be either Salman Khan, Hrithik Roshan or any of the other Khans (Shah Rukh, Aamir).

"Hey Baby" also stars Vidya Balan, Fardeen Khan and Riteish Deshmukh and will be shot in several locations across the globe.