The unidentified representative said Kardashian, 30, and Disick, age not reported, recently learned their first child will be a boy, People magazine reported online Friday.
An unidentified source said the two minor TV personalities, who had split up in February, excitedly welcomed the news they would have a son sometime near Christmas.
"Kourt and Scott are psyched about having a baby, but having a boy is really exciting for them. She can't wait to buy all sort of boy's clothing," the source told People magazine. "And (her brother) Robert is also eager to have a little nephew."
A baby shower for Kardashian, who appears on the reality series "Kourtney and Khloe Take Miami," has been scheduled for Nov. 14.
"I'm sure my mom has been planning this since I was little," Kardashian said in September. "She is big on showers, so I'm sure mine will be a big event."