SBW's baby may be born a Kiwi

Parents-to-be Sonny Bill Williams and wife Alana Raffie plan to be based in New Zealand.

Expectant Williamses heading back to NZ after NRL season.

Sonny Bill Williams' baby may be born a Kiwi as he and pregnant wife Alana plan to be based in New Zealand before the birth.

The league and union star celebrated his 29th birthday last Sunday with a large family gathering in Sydney. But most eyes were on his new wife and her unmistakable baby bump.

There has been speculation about a baby after they secretly married in August last year. Williams has called his wife "mumsy" on social media, and the baby is reportedly due in November.

Sonny Bill Williams and his wife Alana Raffie (bump showing) at his 29th birthday celebrations in Sydney.

It has already been confirmed the Williamses will move to New Zealand at the end of the NRL season. The grand final is on October 5.

Williams has signed two-year deals to play for Counties Manukau and the Chiefs, aiming to make the All Blacks squad for the 2015 Rugby World Cup.

He has made no secret of his desire to start a family and dotes on his young nieces and nephews, some of whom live with him in his palatial Sydney home.

In an interview with The Footy Show last year, he was asked where he wanted to be in 10 years.

"Hopefully, you know, have my own little family of my own and just be concentrating on my kids."

The Herald on Sunday revealed his relationship with 20-year-old "Raffie" in November last year after he posted a photo of the couple on his Instagram page.

They had secretly wed after a whirlwind six-month courtship.

News of their marriage broke in April this year when they jetted off for a belated honeymoon in Bali.