The actress strangely performed the dance in ballet shoes when lavani dancers do it barefeet. Maybe the actress was in dire need of a pedicure, so she preferred do a cover up.
Meanwhile...
Stanley D'Costa who has choreographed the lavani number says, "As a dance form, lavani requires lots of movements of the waist and the hip.
Besides making it look sensual, the dancing has to be complemented with catchy expressions. Vidya has managed to combine grace and sensuality." Ooh la laa...