Nicky Hilton Shares Her Kids Had Their First Sleepover at Sister Paris’ House: ‘They Definitely Stayed Up Late’ (Exclusive) .Linh

Nicky Hilton Rothschild‘s kids adore hanging out with their aunt Paris Hilton.

While chatting with PEOPLE on Tuesday, Oct. 8 at Glamour’s Women of the Year Awards in New York City, the fashion designer, 41, revealed that her kids — daughters Lily-Grace Victoria, 7, and Theodora “Teddy” Marilyn, 6, and son Chasen, 2, whom she shares with her husband of nearly a decade, James Rothschild — recently reached a new milestone.

“They had their first sleepover on Friday at Paris’, ” the mom of three tells PEOPLE, referring to her sister Paris Hilton, 43. “They definitely were up late, but had lots of fun.”

Hilton Rothschild proudly adds that her little ones didn’t even call their mom once. “They loved it. Every minute,” she says. “I’m bringing them over to Paris again whether she likes it or not.”

Hilton Rothschild recently spent some time with Hilton’s son Phoenix, 20 months, sharing content from the trio’s spa day on Saturday, Oct. 5. The heiress and DJ re-shared a picture from Hilton Rothschild’s Instagram Stories of Hilton and son Phoenix dressed in pink outfits and headbands for a spa day.

Hilton notably has a home wellness center that she calls the “sliving spa,” which contains cryotherapy and facial machines and a red light therapy bed.

The “Stars Are Blind” singer, also showed off some decorations in an Instagram Stories video to mark her sister’s 41st birthday. Rose gold balloons that read “HAPPY BIRTHDAY NICKY” are seen surrounded by smaller pink and silver balloons.

“So cute,” Hilton can be heard saying as she passes her dogs and a “HOUSE OF SLIVING” sign on the floor.

Hilton is also mom to 10-month-old daughter London, and shares both kids with her husband Carter Reum.