Nicky Hilton is congratulating Paris Hilton on the birth of her first child and confirms her older sister’s newborn is a boy.

On Tuesday, Paris, 41, took to Instagram to announce the surprise arrival of her and husband Carter Reum’s first child together. The couple, who wed in 2021, reportedly welcomed their son, whose name has yet to be revealed, via a surrogate.

On Wednesday, the socialite’s younger sister Nicky, 39, shared a heartwarming message for the new mom, confirming that she’s now an aunty to her nephew.

READ MORE: Nicky Hilton Shares Maternity Shot After Announcing She And James Rothschild Are Expecting Third Child

“Welcome to mommyhood @ParisHilton! So so incredibly happy for youuu! It’s the most beautiful ride. There is no greater love,” she captioned a throwback photo of her and Paris as children with their mother Kathy Hilton.

“You are going to be the best mommy. What a lucky boy!” she concluded.

READ MORE: Nicky Hilton Recalls How Carter Reum Asked Her Permission Before Popping The Question To Paris Hilton

Nicky is married to James Rothschild, a founder and managing partner of Tru Arrow Partners- a global growth technology firm. The couple, who wed in 2015, share three children together- daughters Lily-Grace Rothschild, 6, and Teddy Marilyn Rothschild, 5, and a seven-month-old infant son, whose name has also yet to be revealed.