Ryan Piers Williams and America Ferrera. Photo: Michael Stewart/FilmMagic

On Tuesday, America Ferrera revealed in an Instagram post that she and filmmaker husband Ryan Piers Williams have welcomed their first baby — a little boy named Sebastian.

The post, which features one of Sebastian’s adorable little feet in his parents’s hands, reads: “When 2 become 3 … Welcome Sebastian Piers Williams - aka Baz! Mom, Dad, and Baby are happy, healthy and totally in love!”

Ferrera, who currently stars on the sitcom Superstore, announced her pregnancy in a cute New Year’s Eve post — and soon after, she celebrated the news with her Sisterhood of the Traveling Pants co-stars (and best friends) Alexis Bledel, Amber Tamblyn, and Blake Lively (as seen in a pic posted by Tamblyn that also called to the friends’ work on the Time’s Up initiative).

Didn’t think anything could beat kicking off the new year with the #TIMESUP initiative, but then... pic.twitter.com/WLbtL6f8qV — Amber Tamblyn (@ambertamblyn) January 2, 2018

This means all four members of the Sisterhood are now mothers: Alexis Bledel had a boy with husband Vincent Kartheiser in 2016; Tamblyn had a daughter with husband David Cross in 2017, and Lively has two daughters with husband Ryan Reynolds.

Congrats to the happy family!