"Look at my son, pride is not the word I’m looking for, there is so much more inside me now. When you smile, I fall apart ," Stamos captioned the shot of Billy sleeping on his chest, quoting the "Dear Theodosia" song from Hamilton.
The Fuller Housestar, who sported a black T-shirt and his signature smoldering gaze in the photo, continued: "Listening to 'Dear Theodosia' - Goosebumps /Tears - Damn you #linmanuelmiranda. Your message is more needed now than ever. Your genius is time-released!"
This isn't the first time Stamos has gushed over his son. "It's more beautiful than I imagined," he told ET's Lauren Zima back in April of fatherhood. "Everything is more colorful, more exciting. Music, you know, sounds better. He's just a beautiful little boy."
He also praised McHugh, 32, for how she handled their son's delivery.
"My wife was so beautiful and so graceful through it all, like she does life. I mean, she just kind of breezed through," Stamos said. "I hate to tell women, but she did it in about 20 minutes. It happens so fast and then they were like, 'Take pictures! Grab her leg!' And then it was over, but it was just beautiful."
"He used to say he's not going to change any diapers … and he's changed so many diapers! He totally doesn't mind it. It's beautiful seeing [John] with Billy. It all feels so right. It feels like this is the way it should've always been," McHugh mused. "He comes so naturally to fatherhood and I love watching it. I stare at the both of them all the time. [John is] 100% full-on active and fantastic ... He's perfect, he's a perfect father. I can't wait to give him more [kids]."