The newborn has been named Louie Mark Roderick Stewart.
The 28-year-old captioned his latest Instagram post with: “Welcome lad, you American, British, Croatian, Kiwi. Louie Mark Roderick Stewart 5.12.23.”
Hunter commented on her son’s post, “Welcome you beautiful Angel 💙”.
Her ex-husband Sir Rod Stewart’s current wife, Penny Lancaster, also commented, “Congratulations ❤️ that’s the look of love. Can’t wait for a hug 🤗”.
Hunter (53) said earlier this year that she was “so excited” to become a grandmother.
Liam and his partner Nicole announced their pregnancy via Instagram in January this year.
Hunter, from Glenfield in Auckland, began her modelling career at 16 in the Benson & Hedges 1986 Fashion Design Awards at the Michael Fowler Centre in Wellington.
She is best-known to many New Zealanders as being the “Trumpet Girl” in Tip Top ice cream advertisements from the 1980s.
She spoke to The New Zealand Herald last year about her career, her beauty routine and acting ambitions.
Hunter has carved out a new career as a yoga teacher, leading retreats in India, Bali and New Zealand. She will add Hawaii to the list this year. Sometimes she teaches alongside her daughter, and it’s an activity that brings the pair closer together.
The two met in a Los Angeles nightclub when she was 21 and have two children - daughter Renee, born on June 1, 1992, and Liam, born on September 5, 1994.
They separated in 1999 but officially divorced in 2006.
Sir Rod has eight children with five women, including sons Alastair and Aidan with his current wife Penny Lancaster.
He also has Kimberly (43) and Sean (42) from his first marriage to actress Alana Stewart (77), and his daughter Ruby (35) is from a relationship with 63-year-old model Kelly Emberg.
His first child was Sarah Streeter (59), who was raised by her adoptive parents Gerald and Evelyn Thubron, and he is granddad to Kim’s daughter Delilah, 11.
The Maggie May singer drew great reviews for his concerts in Dunedin, Auckland and Napier alongside Cyndi Lauper last month.
