Rumer Willis' supposed fans at The Sayers Club reportedly "secretly laugh at her".
The 24-year-old daughter of Bruce Willis and Demi Moore performs two songs on Tuesdays at the Los Angeles venue in exchange for free alcohol.
Apparently event organisers aren't interested in fostering Rumer's fledgling musical career.
They are most concerned with providing comic relief to their customers.
"The venue likes Rumer to sing every week because she brings publicity, but the truth is, she's horrible," a source told Star magazine.
"The regulars all secretly laugh at her, because she's always bragging that she sounds like Lana Del Rey when, really, the audience can't stand to listen to her."
Rumer is known to be somewhat of a party girl.
Her health may be adversely affecting her singing ability.
"Rumer is a chain-smoker and says she feels like smoking cigarettes gives her voice a raspier edge, like Lana's," the source said.
"But all it really does is cause her to cough constantly on stage, which adds to her poor performance."
© Cover Media