Kim Kardashian & Kanye West Welcome Baby Number 4!

This Mother's Day is bound to be extra special for Kim Kardashian West, as the reality star and mogul is officially a mama of four! Kim announced on Twitter Friday that her fourth baby with husband Kanye West, a son born via surrogate, had arrived.

“He's here and he's perfect!” Kim gushed.

Kim and Kanye are also parents of 5-year-old daughter North, 3-year-old son Saint, and 16-month-old daughter Chicago. So, who does the newest member of the Kardashian West family resemble?

“He's also Chicago's twin lol I'm sure he will change a lot but now he looks just like,” Kim revealed.

Kim confirmed baby number four's arrival, but it was actually older sister Kourtney who spilled the beans to the world yesterday that Kim's surrogate had gone into labor. Kourtney made a surprise appearance on Thursday's “The Ellen DeGeneres Show,” joined by her kids Mason, Penelope and Reign as well as Kim's children to drop some exciting news on her mom Kris.

“My mom doesn't even know this, but Kim's surrogate went into labor, so she's at the hospital,” she shared.

Kim announced in January that she and Kanye were expecting their fourth child. She told Jimmy Fallon in February, “My house is so full [but] I heard that parents of four are the most enlightened and calm of all parents.”