On Wednesday, the former Saved by the Bell star took to Twitter to announce the big news, tweeting, "So in love with our new baby girl, Lachlyn! Born last night 2/17 Mum and baby are healthy and happy. 2 boys, 2 girls, too perfect!"
Aside from sharing his baby's name, Gosselaar also Instagrammed one of the cutest baby pics ever, captioning the adorable photo of his sleeping baby, "She's a 'mouth-breather' like her Daddy. My sweet little angel."
This is Gosselaar's second child with McGinn after they welcomed their son, Dekker Edward, in October 2013. Gosselaar has two other children, 10-year-old son Michael and 8-year-old daughter Ava, with his ex-wife, Lisa Ann Russell.