"I believe @bipsluvurself (Bipasha) when she says she is not in the Amar Singh tapes. Doesn't sound like her at all," Nandy posted on his Twitter page.
Sonam added: "I agree. A bunch of vicious losers are doing this! It doesn't sound like her at all. It's so improbable, it's almost funny."
Bipasha herself has denied that it's her voice in the controversial tapes, which were barred from publication in the media since 2006 until Wednesday when the gag order was lifted by the Supreme Court.
Former beauty queen-turned-actress Celina had also extended support to Bipasha.
She said she had heard the tapes herself, and was confident that the girl in the tape was not Bipasha at all.