Kim Kardashian and Kanye West have welcomed their fourth child 1 month ago

Kim Kardashian and Kanye West have welcomed their fourth child

"He's here and he's perfect."

Kim Kardashian and Kanye West have welcomed their fourth child, a son, via surrogate.

The Keeping Up With the Kardashians star confirmed the news on Twitter, where she said he was "perfect."

There's no word on the newborn's name just yet.

The news that their surrogate had gone into labour was confirmed on Thursday, when Kourtney Kardashian surprised Kris Jenner on the Ellen DeGeneres Show. 

She brought her three children - Reign, Penelope, Mason - as well as Chicago, Saint and North onto the show for a Mothers' Day surprise.

Kourtney explained that it had meant to be Kim who would appear on the show - however, their surrogate had gone into labour.

A visibly-shocked Kris asked her: "What! What are we doing here?! For how long?"

“And nobody knows, so everyone in the audience don’t tell,” Kourtney laughed.

It was first reported that Kim and Kanye were expecting their fourth child in January this year.

Kim confirmed the news a few weeks later, during an appearance on Watch What Happens Live with Andy Cohen. 

She added:

“It’s a boy, I think it’s been out there.

“I got drunk at our Christmas Eve party and told some people. I can’t remember who I told because I never get drunk."

The couple are already parents to North, 5, son Saint, 3, and daughter Chicago, 1.