The Kardashian-West family keeps getting bigger.

On Thursday night, it was reported that Kanye and Kim's surrogate had gone into labor with the couple's baby boy. The news was revealed during a special Mother's Day taping of The Ellen DeGeneres Show, in which Kris Kardashian was joined by all of her grandchildren.

According to TMZ, Kim was initially tapped to appear in the episode, but had to back out because of "urgent matters." So, big sister Kourtney stepped in and explained why Kim couldn't make it. And surprisingly enough, matriarch Kris had no idea her seventh grandchild was being born.

"So, my mom doesn't even know this, but Kim's surrogate went into labor," Kourtney said in front of the live audience. 

"What are we doing sitting here ... Fire up the car!" Kris responded.

"We had to keep it quiet," Ellen explained. "That's why [Kim's] not here."

Check out the emotional moment in the clip below. 

Earlier this week, a number of outlets reported Kim and Kanye's surrogate had gone into labor on the day of the Met Gala. Kim quickly shot down those rumors.

The baby will Kim and Kanye's fourth child, following North, Saint, and Chicago. The latter child was also born through surrogacy; however, Kim and Kanye ended up using a different surrogate for baby No. 4. 

We'll keep you posted as more information about the Kim and Kanye's latest addition becomes available.