The Keeping Up with the Kardashians star, 38, confirmed on Twitter on Friday that she and her rapper husband have welcomed their fourth child, a son, via surrogate.

“He’s here and he’s perfect!” Kardashian West tweeted.

PEOPLE confirmed on Jan. 2 that the couple would welcome a sixth member to their brood that also includes daughters Chicago, 15 months, and North, 6 next month, plus son Saint, 3.