Nicky Hilton told her sister Paris to "not miss the small moments" of motherhood.
Nicky Hilton reveals her motherly advice to sister Paris
The 39-year-old star - who has daughters Lily-Grace, six, and four-year-old Teddy as well as a 10-month-old son whose name she is yet to reveal with husband James Rothschild - explained that when her elder sister Paris, 42, welcomed son Phoenix in January this year with her husband Carter Reum, she told her that there is such a "short window" that babies are so small and reminded her that she needed to look out for the "new things" that will be happening all the time.
She told E! News: "My advice always is to not miss the small moments. There's such a short window that they're so small, and new things are happening every day. Like, Paris always says her son looks different every day. She is so happy. She's so content! I was just over there last week and just hanging out in the nursery with her and her son, and she's so complete is the word I'd use."
Nicky went on to add that because her brother Barron Hilton II and his wife Tessa welcomed eight-month-old Caspian Barron last September but also have Milou Alizée, three, together it was "funny" how the family was initially made up of a string of girls before welcoming three boys within a year.
She added: "Funny, we had all girls in the family and, in the last year, my brother had a son, Paris had a son and I had a son. So, we've been flooded with boys, and it's amazing to see the bond between them.
"It's a lot of parallel playing, and we put them on the floor, and they hang out next to each other and we hang out. But that's sort of how it was growing up with my mom, and her sisters, and our cousins and we're all best friends like sisters."
Tagged in Paris Hilton Nicky Hilton Phoenix