The actress was found hanging in her room. She was taken to a corporate hospital, where Monal was declared dead, they said.
The reason behind taking this extreme step by the actress was not immediately known. A case had been registered, police said.
The 21-year old actress is survived by her parents and three sisters, including well known Tamil actress Simran.
Her body was taken to government Royapetta hospital for post mortem, police said.
Monal was adopted by her maternal aunt, with whom she was living for the past three years.
She had acted in six Tamil films, including the box-office hit, Samuthiram and in two Malayalam films.
Simran is abroad in connection with a film shooting. Decision on Monal's funeral will be taken only after hearing from her sister, the sources added.