Hugh Hefner's former girlfriend Holly Madison says the Playboy mogul has moved on and begun a new relationship with 19-year-old twin Playmates, Us magazine reports.

Holly, 28, says she is not jealous of the girls and in fact introduced Karissa and Kristina Shannon to Hefner after she directed a pictorial featuring them this summer.

"They're a lot of fun," Holly told Us at a bash in Hollywood. "I would never try to personally pick Hef's new girlfriend. I would like him to take his time and actually get to know somebody -- which he never does! But as long as he's having fun, I'm happy for him!"

Holly said she hopes Hef's new young beauties realize and can handle what they are now embarking on. "I just hope that they can take this new fame with a level head," she said.

Asked by Us whether she's still living at the Playboy mansion, she said, "I haven't really changed anything. Like, as far as the whole transition thing, I just leave that up to Hef to talk about and make decisions on. Everything's good."

Holly gained fame along with Hefner's other two girlfriends -- Bridget Marquardt and Kendra Wilkinson -- by appearing on his reality show "The Girls Next Door," which airs on the E! network.