If Lady Gaga's performing onstage, you better listen. And if you don't, she'll stop singing.

When a loud crowd still chatted at the Plaza Hotel where Gaga was performing jazz tunes Friday night, she stopped in the middle of her second song because of the noise.

"Will you (expletive) shut up? We're playing some jazz," she told the crowd of a few hundred in New York City. "Goddamn rich people."

Gaga sang at the New York Fashion Week party by Harper's Bazaar, where attendees included Donatella Versace, Liberty Ross, Brooke Shields and R&B singers Maxwell and Miguel.

The 28-year-old pop star sang songs from her collaborative jazz album with Tony Bennett called "Cheek to Cheek," to be released Sept. 23. She shut up the crowd at moments when she hit impressive high notes.

Gaga sported short blond hair and a black leather dress she said her sister created for her.

The New York-born performer dedicated a cover of Cole Porter's "Ev'ry Time We Say Goodbye" to her family and boyfriend, "Chicago Fire" actor Taylor Kinney.

"So, if you all keep it down while I sing my boyfriend a song, I'd appreciate it," she told the audience at the black-tie event.

The Friday event honored women in fashion, including Linda Evangelista, Shields and Gaga.

"An icon, I believe, is somebody that has a strong message behind their beauty and I think all of the women that are here tonight have that," Gaga said on the red carpet. "I'm not sure that I have it, but I am pretty happy to be on the list with all these super models, so thank you."