The Kahaani star made the comments after Amitabh Bachchan lent his voice to one of the tracks in the movie.
Explaining why she is not part of the soundtrack, Balan stated: "So far no, because I don't know. I am not even a bathroom singer. So I am happy listening."
Bachchan, who provides vocals on the track in the Kolkata-set film, said: "May I just say that singing 'Rabindra Sangeet' for the first time was the greatest revelation. The beauty of the language, the lyricism of the tune and its dhun (music) are outstanding.
"This particular world famous number 'Ekla Cholo', expounding to all that if no-one came to you on your calling, walk alone!! And what a fabulous song has been incorporated by Vishal-Shekhar. Truly awesome and worthy of all award."
Responding to Bachchan's musical commitment to the project, the actress said: "That is very, very kind and generous of him. He has sung a song for us. It is a very special song for Kolkata and all the Bengalis. It has been sung by Mr Bachchan, so it becomes all the more special."
The two actors had previously worked together on Paa, alongside Abhishek Bachchan.
Kahaani is scheduled to release March 9.
Watch a track from Kahaani here: