Watch Pregnant Khloé Kardashian Learn the Sex of Her Baby with Tristan Thompson

How exciting!

Surprise! Khloé Kardashian‘s baby gender reveal “shocks” sister Kourtney Kardashian on the season finale of their reality show.

In a promo for next week’s episode of Keeping Up with the Kardashians, the mum-to-be teases, “Do you want to know what I’m having?”

“I’m shocked,” says Kourtney, 38, before she and Kim Kardashian West envelop their sister in a hug.

Khloé, 33, officially announced her pregnancy in December 2017, and PEOPLE has already confirmed she is expecting a son with NBA star Tristan Thompson.

On Sunday night’s episode, Khloé grappled with extreme pain during her first trimester, side effects of her progesterone pills.

“I just feel sick every night,” she said. “I feel gross. I physically can barely walk.”

It’s been a baby boom for the family: Kim, 37, welcomed her third child, daughter Chicago, via a surrogate in January, and sister Kylie Jenner, 20, welcomed her first child, daughter Stormi, in February.

This article originally appeared on PEOPLE

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