"Welcome to the world Kian Alexander MacKay. We are overjoyed with our baby boy," MacKay announced on his Twitter account.
The boy, born Monday morning in Ottawa, weighed 8 pounds, 2 ounces, said Paloma Aguilar, MacKay's press secretary.
MacKay and Afshin-Jam were married in January 2012, the Canadian newspaper The Globe and Mail said.
Celebrity Couples of 2014 [PHOTOS]