John Stamos is a dad! See the adorable pic of his baby son

Uncle Jesse is now Papa John.

"Fuller House" star John Stamos has become a first-time dad at 54, announcing the birth of his son Billy with a sweet photo of them together on Instagram early Monday.

"From now on, the best part of me will always be my wife and my son,'' he wrote. "Welcome Billy Stamos (named after my father) #NotJustanUncleAnymore#Overjoyed."

Stamos has been gushing with excitement over becoming a dad ever since he and his wife, Caitlin McHugh, announced the pregnancy in December. McHugh, 31, and Stamos were married in February.

Last month he posted a funny “Full House” throwback pic to show his anticipation about the coming birth of his son.

"I've waited my whole life for this," Stamos told Entertainment Tonight earlier this month. "I just can’t. I'm already so emotional and so excited ... I've been dreaming about our baby. I mean, I am really excited."

"I don’t know what I would do if I wasn't having a baby right now. Like, I've done everything anyone could ever ... I've had the most beautiful blessed life on the planet, and the most honest real thing I could do I haven't done."

Congrats!

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