John Stamos Cries in His First Interview About Fatherhood

"It's so beautiful having a baby," the actor tells Ryan Seacrest

Four days ago, John Stamos became a father—something he still can't wrap his head around!

In his first interview since becoming a father, the 54-year-old Fuller House actor—who is hosting WE Day in L.A. today—gushed over his wife, Caitlin McHugh, and his son, Billy Stamos. John's newborn arrived two months after he tied the knot and six months after he proposed. "We just kind of crammed everything in, because it's been so great," the actor joked when he called in to On Air With Ryan Seacrest. "It's so beautiful having a baby. You have to do it, Ryan!"

John said he named Billy after his father, "who was my hero. I hope I live up to what my dad did." Though John' father died in 1998, he said, "He was always bigger than life to me so I'm happy to honor him with our little Billy. I'm starting to cry right now, Ryan! I am so emotional!"

Since Billy's birth, John laughed, "Everything is greener and bluer. I'm looking out the window right now and I see all kinds of different colors—different poop colors. There's green, there's yellow...I saw some blue this morning, which I thought was weird." Jokes aside, John said he "always wanted" to become a father. "I guess I was waiting for the perfect wife, which I have."

Speaking of Caitlin, John raved, "She's been so graceful through this whole thing." He guessed her delivery lasted just 20 minutes. "A little baby came out and he looked just like Don Rickles!"

Watch E! News tonight, at 7 and 11, for the latest scoop on John's mini-me.