George Clooney and wife Amal welcome birth of twins Ella and Alexander

Actor George Clooney's wife Amal has given birth to twins, the couple's publicist said.

According to Stan Rosenfield, Ella and Alexander Clooney were born in a London hospital on Tuesday morning.

He said the babies were both "happy, healthy and doing fine", and joked: "George is sedated and should recover in a few days."

The news comes weeks after Gravity star Clooney told the media that he was well prepared for fatherhood.

He told US site Extra: "I know what I'm in for," and said of his wife: "She is amazing. I don't have anything to do."

The actor, 56, married the lawyer, 39, at a lavish Venice wedding in September 2014.

News of the couple's pregnancy broke in February when it was announced on a US talk show.

Clooney's close friend Matt Damon later confirmed that the happy news was true.

He told Entertainment Tonight Canada: "I was working with him last fall and he pulled me aside on set and, I mean, I almost started crying.

"I was so happy for him. And I was like, 'How far along is she?' And he goes, 'Eight weeks'.

"(I said) 'Are you out of your mind? Don't tell anybody else! Don't tell anybody else! Don't you know the 12-week rule?' Of course he doesn't. I was like, 'Just shut up, man'."

Damon, who starred alongside Clooney in Ocean's Eleven, added: "I'm thrilled for him. She's amazing. He hit the jackpot. Just on every level. She is a remarkable woman. They're going to be great.

"They're going to be awesome parents. Those kids are lucky."

Other notable celebrity multiple pregnancies this year have included singer Pharrell Williams, whose wife Helen Lasichanh gave birth to triplets in January, and Beyonce, who is expecting twins with husband Jay Z.

Comedian and TV host Ellen DeGeneres was one of the first celebrities to congratulate the new parents on social media.

She tweeted: "Welcome to the world, Ella and Alexander Clooney. Congratulations, George and Amal, or as I'm now calling you, Ocean's Four."

Mia Farrow also added her best wishes, tweeting: "Wishing Ella and Alexander Clooney a warm welcome and every blessing - and congratulations to Amal and George!"

US journalist Katie Couric also offered her congratulations, tweeting: "Congratulations to Amal & George Clooney on welcoming their twins, Ella and Alexander!!"