Nicky Hilton has given up sexy Halloween costumes now that she's a mum

Nicky Hilton is leaving the sexy Halloween costumes to her sister, Paris Hilton.

Now that the 36-year-old is a mum-of-two, she no longer thinks it's appropriate for her to rock raunchy numbers.

"I keep my costumes pretty simple. I do not do the elaborate make-up… I'm happy with a simple face mask," she told Page Six at the Angel Ball in New York on Monday. "Besides, I am a mother of two little girls, I can't do the risqué look anymore."

In the past, the socialite-turned-fashion-designer has dressed up as a naughty French maid, sexy kitty complete with leotard and fishnets, and even frocked up as a flight attendant at the late Hugh Hefner's Halloween party. Back in 2002, she wore a silky white negligee to Heidi Klum's annual Halloween bash.

However, in recent years, Nicky has gone conservative with her costumes. In fact, last year, she didn't even wear a costume — instead, she emulated Paris' 21st birthday look by wearing a dress she likely already owned in her closet.

At Rande Gerber and Cindy Crawford's annual Casamigos party in 2015, Nicky dressed up as a demure Pocahontas next to Paris' belly-baring warrior princess outfit.

Nicky's Halloween confession comes after the star revealed to People magazine last week that her daughters have been raiding her closet.

"They are definitely going into my closet, taking all the shoes down, trying them on. They're into shoes and bags," said the heiress of her girls, Lily-Grace, three, and Theodora, 22 months. "I had to hide them all the way at the top because they were ripping them down, and all the crystals come off."

That doesn't mean Nicky — who is married to British banker James Rothschild —  is no longer into Halloween. She's still on board with the holiday and even got her daughter into the celebrations earlier this month.

"Getting into the Halloween spirit very early this year…," she captioned a photo of Lily-Grace playing as Elsa from Frozen as they holidayed in South Hampton, New York.