"Your boy Diddy is a champion," the hip-hop mogul says of his growing family

Not only are Sean “Diddy” Combs and girlfriend Kim Porter expecting, as the hip-hop mogul told PEOPLE exclusively in August, they’re expecting twins.

“After Tom and Kate, and Brad and Angelina, I had to find a way to top them all,” Diddy tells PEOPLE. “This is truly a blessing and we’re really happy about the news.”

The babies are due in December.

In a video posted Monday on his MySpace.com page, Diddy and the visibly pregnant Porter are shown standing outdoors as the words “Special Announcement” flash at the bottom of the screen. “Hey, whassup y’all,” Diddy says. “We interrupt your browsing for this emergency announcement.”

He goes on to talk about a recent morning when he woke up next to Porter and noticed she looked especially big for her stage in her pregnancy. “I said, ‘Baby, I think you’d better go to the doctor, ’cause you’re kinda big. You look like you’re ready to give birth right now,’ ” he says.

“So we went to the doctor, and guess what?” he continues. “Your boy Diddy is a champion.” Here, Porter laughs. “I am a champion,” Diddy goes on. “The doctor told me and Kim, and I’m telling you right now, no press announcement, I’m just telling people in my family, that I’m having twins. It is official.

“Two more Combs. Two! World, you’re in trouble now.” He kisses Porter’s belly and she asks if he’s going to reveal the twins’ sex. “We can’t tell ’em the sex yet,” he says. “We can’t tell y’all everything. Some things gotta be private.”

Combs and Porter already have a son, 8-year-old Christian, and Combs has another son, Justin, 12, with fashion stylist Misa Hylton-Brim.