How exciting!!! Mark Walhberg is expecting baby #3 with his fiance, Rhea Durham! Of course, they haven't actually gone public with the news yet, they just have talkative friends who have said that Rhea will be giving birth to a boy this September.

"Mark is thrilled to be having another baby," says one pal. "He is an amazing dad, and his two children are his world. He always used to joke about wanting at least a dozen kids, but it looks like he wasn't joking after all."

And this third baby won't push Mark any closer to actually setting that wedding date. His friends say that even though things are great with the couple, he's just marriage shy.