Mac and Dee and baby makes three! Er, four. People reports that It’s Always Sunny in Philadelphia actors Kaitlin Olson and Rob McElhenney welcomed a son, Leo Grey McElhenney, in the wee hours Thursday, April 5. Leo is the couple’s second child; their first son, Axel Lee, was born in the fall of 2010. Olson and McElhenney have starred in FX’s quirky comedy since 2005. The pair married in September 2008.