Clooney, who spoke to E! while promoting his movie "Suburbicon" at CinemaCon, said he is thrilled to become a parent.
"Can you believe it? [I'm] even happier [than before]," he gushed. "I didn't know that we'd have kids. I was very happy that we were going to get married and then [a pregnancy] seemed like the next step."
Clooney married Amal in Venice, Italy, in September 2014 after less than a year of dating.
He gave an update on the 39-year-old human rights lawyer an interview with "Extra" at the convention.
"She is doing really great. She's amazing. I don't have anything to do. There is nothing I can do to help, but make tea and stuff," the star said.
Clooney starred as Dr. Ross in Seasons 1 through 5 of "ER," and appeared in Seasons 6 and 15.
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