and longtime girlfriend
celebrated the birth of their first child, son Harry
, just before midnight on Monday. Letterman broke the news on Tuesday's Late Show
. "First thing I took him home and dangled him over the balcony," joked the 57-year-old funnyman, who named his first-born after his late father. Naturally, Letterman used the birth as fodder for his top 10 list. Among the reasons the late-night vet was excited to be a dad: "There is now tangible evidence I have sex." Eh, I'm still not convinced.