"Mark-Paul Gosselaar and wife Catriona are thrilled to announce they're expecting their first child together in September," his rep says in a statement to Us. Gosselaar is already dad to son Michael, 9, and daughter Ava, 6, with ex-wife Lisa Ann Russell.
"We are all really excited for the arrival of our new addition. We've always wanted a big family," Gosselaar tells Us. "The kids are looking forward to a little sibling, and are asking a lot of funny questions right now."