"She is a trooper, and I can't wait for the baby," Paris Hilton praised sister Nicky Hilton Rothschild, who is pregnant with her second child
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Nicky Hilton Rothschild and James Rothschild’s second child on the way is going to have the most fabulous aunt.

Paris Hilton is so excited for her sister’s new bundle of joy to arrive, revealing to PEOPLE at the Hollywood, California, premiere of Demi Lovato: Simply Complicated, “She’s doing amazing.”

“She’s literally the most beautiful pregnant woman I’ve ever seen in my life,” shares the 36-year-old heiress.

Hilton adds that her sister hasn’t felt “sick” during this pregnancy, explaining, “She is a trooper, and I can’t wait for the baby.”

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The star is hoping that she’ll be getting a nephew this time around — “I hope it’s a boy,” she says — Hilton Rothschild, 34, and her husband already share daughter Lily-Grace Victoria, 15 months.

Either way, though, Hilton says her little sister is ready for baby No. 2. “She’s going to be amazing,” says Hilton, adding, “Lily-Grace actually just started walking, so that was amazing to get a video the other day of that. We’ve been waiting for that.”

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Hilton Rothschild’s rep confirmed her second pregnancy to PEOPLE in July. The couple were married in a lavish Kensington Palace ceremony in July 2015.

Hilton has been dating The Leftovers star Chris Zylka since earlier this year. “I’ve never been happier,” she tells PEOPLE. “He’s my soulmate. I feel like he’s my best friend, and we’re really excited for our future together.”

As for starting her own family, the older sister teases, “We’ll see.”