The six-time All-Star selection made it official with the following post on Instagram:
MediaTakeOut.com first reported Nina was pregnant in January after pictures of her sporting a baby bump surfaced.
Russell and Nina have been married since 2015.
The 28-year-old former UCLA standout has thrived since Kevin Durant's departure to the Golden State Warriors. Westbrook is averaging career highs with 31.2 points and 10.6 rebounds to go along with 10.3 assists per game and is a leading MVP candidate.