You'll never believe this, but Kim Kardashian took to her Twitter account soon after sister Kourtney gave birth yesterday. Wrote Kim:

"I'm an auntie!!!! My little Mason Dash Disick is here!!! We are so happy!"

From there - ON THE SAME DAY THEIR SISTER/DAUGHTER BECAME A FIRST-TIME MOTHER - Kim and Kris Jenner appeared on E!'s Chelsea Lately. Joked the host:

"When I found out [Kourtney] went into labor and had the baby, I said, 'Oh, do we have to get a replacement guest?' And [my producers] were like, 'No, they would never miss a television appearance.'"

How true. The only surprising thing was that Kim and Kris didn't drag newborn Mason in front of the camera along with them.