The party, which was held at a roller disco in Los Angeles, had the stars trade in their heels for roller skates. The bash was for celebrity stylist and mentor on America's Next Top Model, Johnny Wujek.
Katy even dressed in ‘90s wardrobe, wearing a floral tank top with matching leggings underneath her jean shorts and pink cat-eye classes. Amber even joined in on the theme, wearing a lacy top and ripped denim shorts.
We wish we could have been there as they looked like they were having a blast. Check out the gallery above to see more of the roller party!