While promoting her new E! show, "Kourtney & Khloé Take Miami," on the "Today" show on Thursday (August 13), Kourtney Karadashian confirmed that on-again, off-again boyfriend Scott Disick is the father of her first child, who is due in December.

Kardashian, 30, announced the news late Wednesday to E! News, but declined to identify the baby's father. "You're going to have to see on the show," Khloé and Kim's older sister said.

The socialite and reality-TV star said she was "shocked" to discover that she was pregnant. "I found out I was pregnant [at the end of shooting]. We were in the Everglades, and I kept feeling nauseous and sick," Kourtney told E!. "I just kept thinking something wasn't feeling right. ... Literally, I took like 20 tests. I went to the doctor and he confirmed the news. I was just so shocked."

The eldest Kardashian sibling shared that her mom, Kris, who also starred alongside her daughters on "Keeping up with the Kardashians," is excited about the news that a new baby is being added to the family "right around Christmas time." "She was begging us to have kids, she's really excited," she told Ryan Seacrest.

According to People, Kardashian and Disick broke up earlier this year in January. But the pair have been seen together several times since then, including in July in the Hamptons, where they had dinner together and Disick reportedly introduced Kardashian to a friend as his girlfriend.