"I just stood there for like 10 minutes, just staring at this piece of paper going, 'What, two?!' " George Clooney told CBS Sunday Morning's Tracy Smith

George Clooney is reflecting on learning he would not only be a father, but a father of two.

In an interview with CBS Sunday Morning that aired this weekend, the actor discussed his new post-apocalyptic thriller The Midnight Sky and life at home with wife Amal Clooney and their twins Ella and Alexander, 3.

Of the couple's ultrasound appointment, Clooney, 59, told CBS News correspondent Tracy Smith, "[The doctor said], 'You got a baby boy.' [I was like], 'Baby boy, fantastic!' Then they go, 'And you got another one there!' "

"I was up for one!" he joked, laughing. "I'm like, 'I'm old.' All of a sudden it's two and I literally ... it's hard to get me to not talk and I just stood there for like 10 minutes, just staring at this piece of paper going, 'What, two?!' "

"But I'm so glad they have each other," Clooney added of the siblings.

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Amal and George Clooney
| Credit: Chris Jackson - WPA Pool/Getty
George Clooney
George Clooney
| Credit: CBS Sunday Morning

Clooney also said that Amal, 42, "changed everything for" him. (The two tied the knot in a lavish 2014 Italian wedding just over a year after they met, and welcomed their twins in June 2017.)

"There is no question that having Amal in my life changed everything for me," he said. "It was the first time that everything that she did and everything about her was infinitely more important than anything about me."

"And then we had these two knuckleheads," the two-time Oscar winner joked of their kids. "It is very fulfilling and something I wasn't at all ... didn't see coming."

He went on to share that the pair initially had no plans for marriage — or children. "We never talked about having kids, and then one day we just said, 'What do you think?' " Clooney recalled.

George and Amal Clooney
| Credit: Kevin Mazur/Getty

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In his interview with CBS Sunday Morning, Clooney also opened up about life in lockdown with his family during the ongoing coronavirus pandemic.

"It's been a while since I did 15 loads of laundry in a day and mopped floors and all these doors over here I stained," he said. "I always say I felt like my mother in 1964, because she had two kids and no help."

"I don't know how she did it now," the actor added. "I have more sympathy for her now than ever."

The Midnight Sky premieres Dec. 23 on Netflix.