03/05/2011 at 02:45 PM EST
's NBA player boyfriend
Kris Humphries has a sweet shot on the basketball court. His voice isn't too bad either.
Kardashian swept into Las Vegas for an event on Friday night and the subject quickly turned to music: This week she debuted
her song, "Jam (Turn It Up)."
"Kris loves it," she told PEOPLE. "He sings it to me on the phone."
The reality starlet, 30, says she enjoyed recording the club-ready song with The Dream and has so far received glowing reviews from her friends in and out of the business and celebrity world.
But Kardashian has no plans to try to conquer the music world. She notes that proceeds from the song go to St. Jude's Children's Research Hospital and, "I did it for fun."
"It was just something I tried," she said at the opening of the Sugar Factory American Brasserie. "I don't have an album in the works. It was just something that kind of got me out of my comfort zone. And I'm really happy I went for it and did something I'm so not comfortable doing."
Kardashian, meanwhile, used her latest trip to Las Vegas to play tour guide to her 13-year-old sister Kylie, who joined her at the opening of the restaurant and high-end candy store.
"She's never been to Vegas before," Kardashian says. "It was really excited for her to drive down The Strip for the first time and walking through casino. She's never seen a casino before so it was really cool."
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