All Blacks and Highlanders star Ben Smith and his wife Kate Menzies have announced the arrival of a baby boy into their family.

Smith announced the birth of the baby, named Walter, on social media last night.

The fullback posted a photo on his Instagram account of him with the baby, who has an older sister, Annabelle Clair Smith, born in March, 2015.

Proud of you @katiesmitzies! Welcome Walter

A post shared by Ben Smith (@bensmith1100) on