"Just took Easter to a whole new level welcoming my soul sister Angi's new bundle of joy, Alakai Lion 🙏👶🙏 And the family grows... #HappyEasterEveryone," the 37-year-old actress captioned the pic.
The image additionally includes Kate's sister-in-law Erinn Hudson. Erinn tied the knot with the How to Lose a Guy in 10 Days star's older brother, Oliver Hudson, in 2006 and the couple are now parents to three kids together.
Later on Sunday, Angi — who is Kate's personal trainer and close friend! — posted a photo of herself with baby Alakai, her older son, and husband.
Kate with her two sons, Ryder and Bing. (Photo Credit: Getty Images)
"God's greatest gift and another reason to give Him all the glory for this most amazing holiday of Grace, miracles, and eternal life 🙏🏻🙌🏻 Thank you everyone for all of your prayers and support during this time. We are so in love," she captioned the family photo.
Kate is similarly a mother to two boys. She previously welcomed son Ryder Robinson, 13, in Jauary 2004 with ex-husband Chris Robinson and son Bingham Bellamy, 5, in July 2011 with ex-fiancé Matt Bellamy.
Check out the gallery to see a guide to Goldie and Kate's extended family!