Who’s Abs Are These? [PHOTO]

Whoa, what a bod!  This star clearly works hard on his midsection.  No muffin top here.  But who does this six pack belong to?

Yep...good ol' Zack Morris.  It's 39-year old Mark-Paul Gosselaar surfing the waves with Breckin Meyer as the actors shoot scenes for their prime time drama Franklin & Bash in Malibu, California.

The former Saved By the Bell star just found out he's going to be a dad for the third time!