Kathy Hilton Reacts to Criticism Over Kim Kardashian's Casual Outfit at Her Holiday Party: 'That's Silly'

Kevin Ostajewski From left: Paris Hilton, Kris Jenner, Kathy Hilton, Kim Kardashian and Nicky Hilton Rothschild

Kathy Hilton is a fan of Kim Kardashian's festive fashion choices.

Asked by TMZ about fans who were "blasting" Kim, 42, for the casual rocker look she wore to the Hilton family holiday party — high-waisted, belted leather Dolce & Gabbana pants and an old-school "Up in Smoke" tour concert T-shirt tucked into her bra — Kathy said, "That's silly; that's ridiculous."

"Everybody's just [supposed] to come as they want and be comfortable," the socialite, 63, further responded when the outlet asked if there was a theme for the evening.

As for whether she considered anything "wrong" with the SKIMS founder's edgy ensemble, Kathy added, "No, no. She always looks beautiful."

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Kevin Ostajewski From left: Paris Hilton, Kris Jenner, Kathy Hilton, Kim Kardashian and Nicky Hilton Rothschild

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Childhood pals Kim and Paris, 41, reunited for the star-studded Christmas party over the weekend of Dec. 17, posting photos on social media of the holiday soirée — which was also attended by Kris Jenner, Paula Abdul, Heidi Klum, Paris' husband Carter Reum and her sister, Nicky Hilton Rothschild.

For the event. Paris wore a red lace minidress and sparkly silver Mary Jane-style heels, while younger sister Nicky, 39, opted for a floral minidress. Kathy wore a festive red checkered gown with a large red bow at the bodice and Kris, 67, rocked a patterned black pantsuit.

Along with the BFF photo taken in front of a white Christmas tree, Paris posted a family picture with Nicky, Kathy and her dad Rick Hilton, a photo with her tuxedo-clad husband, and a shot of herself DJ'ing with Abdul, 60.

"My mom always throws the most iconic parties," Paris wrote on her Instagram page, showcasing a variety of festive snaps from the shindig. "Loved celebrating the holidays with family and friends this weekend. What are your favorite traditions this time of year? #Slivmas."

Kevin Ostajewski Paris Hilton and Kim Kardashian

RELATED: Paris Hilton Shares Throwback Photos with Mom Kathy and Sister Nicky in Matching Christmas Dresses

Kim later attended the Kardashian-Jenner family's annual Christmas Eve party — which, this year, was even further elevated by a performance from Sia!

The mogul went back to her brunette roots for the occasion and wore a sparkling silver chainmail gown.

Held at Kourtney Kardashian's home in Calabasas, California, the bash was also complete with red Christmas trees, plenty of chocolate goodies, an all-red ball pit for the kids and a few songs from Sia herself.

Kim Kardashian/Instagram

In videos shared by a few family members, the Australian musician, 47, could be seen singing alongside Kim's 9-year-old daughter North inside what appeared to be a giant makeshift gift box.

RELATED: Kim Kardashian Returns to Brown Hair for Family Christmas Party: 'We're Back'

Kim Kardashian/Instagram

During their time performing together, Sia and North sang her song "Snowman," as well as her 2014 hit "Chandelier." The nine-time Grammy nominee was dressed in an all white-ensemble, while North opted for a shiny two-piece suit.