Mark-Paul Gosselaar revealed to Us Weekly that he's expecting his fourth child, his second with wife Catriona McGinn; "I'm very excited" -- details! Credit: Tibrina Hobson/WireImage

Time out for some good news! Mark-Paul Gosselaar is expecting his second child with wife Catriona McGinn. The Saved by the Bell alum revealed the news to Us Weekly while attending Disney on Ice's Let's Celebrate with his family in L.A. on Thursday, Dec. 11.

"My wife is due in February with another baby," Gosselaar, 40, told Us. "I'm very excited!" 

The couple, married since July 2012, are keeping the sex of their little one a secret. "We have told our families," the actor said, "but we haven't told them the name."

The Franklin & Bash alum (the TNT series was cancelled last month) and McGinn are already parents to son Dekker Edward, 14 months, who's now walking. Gosselaar also shares son Michael, 10, and daughter Ava, 8, with ex-wife Lisa Ann Russell.

Gosselaar has had plenty of practice changing diapers over the years, joking that he's been doing the dirty work since 2004. As for his oldest? Big brother Michael is now keeping up with Zack Morris and the rest of the Bayside High kids.

"My son just started watching it," Gosselaar told Us. Michael, who was at the event, chimed in: "It doesn't seem like a TV show. It seems like real life. Its not like your normal TV show."