On the latest episode of E!'s "Kourtney & Khloe Take the Hamptons," Kourtney Kardashian and Scott Disick revealed that their third child will be a boy.

In the show, Kourtney explained how their oldest son, Mason, helped reveal the gender of the baby to the family.

"Mason ran in here with the blue stick," she said. "There was a red star or a blue star."

Sister Kim Kardashian shared a home video of the event as they found out about the new addition to their big family. The reveal also shared what Mason, nearly 5, thinks of his future sibling.

"I wanted a girl," he admitted.

However, aunt Khloe Kardashian quickly reminded her nephew about how much fun having a little brother will be,

"Girls don't like aliens and Lego guys," she pointed out. "When you have a brother you can say 'Look at all my Lego guys, brother.' You get to be rough and you can boss him around because you're the older one."

During this season of the E! Network reality show, audiences have been following Kourtney's pregnancy progress. Looking back to Season 9 of "Keeping Up with the Kardashians," Disick was less than thrilled to hear the news that his long-time girlfriend was pregnant again. When Kourtney told him, he responded with, "this ain't good," and, "you just keep suckering me into these kids."

Luckily, the news of the baby's sex was met with much more enthusiasm on Disick's part.

Recently, Kourtney displayed her pregnant body fully when she posed nude for DuJour magazine.

"I really feel so comfortable, and almost at my best, when I'm pregnant," she said according to E! News. "I don't know, I just feel just like it's such an amazing feeling, the transformation that your body goes through and knowing that this is what my body is made to do, there's something about that that's so empowering and beautiful and I just really embrace it."