The naked truth about Heidi Pratt's photos in the September issue of Playboy?

She doesn't bare all.

"She's not nude," her sister Holly Montag told Usmagazine.com Monday at Ryan Sheckler X Games Celebrity Classic in Coto De Caza, Calif. "Her Maxim cover was so gorgeous and tasteful, and I know Playboy is going to be the same. It's really cool that she can be part of the Playboy family. I love it. I go up there all the time and play poker. I love the girls there, and it's very cool to be a part of that legacy."

She is equally psyched for her sister to perform at the 2009 Miss Universe Pageant telecast on Aug. 23.

"She will kill it," Holly said. "I know she will give the best performance ever. She's a phenomenal performer and dancer. That's what she's born to do. I think when she's stepping into her own in singing and concerts, people will see that that's where she really shines."

Oh, and how are things with her new brother-in-law Spencer Pratt?

"We're actually getting along really well right now," Holly told Us. "I don't want to jinx it, but he's been awesome as a brother and better than ever."