In a statement to E! Kourtney said: 'Scott and I are so excited to announce that we are expecting our second child and are thrilled to be expanding the love in our family.'
Kourtney first revealed the news to this week's issue of Us Weekly.
The older sister of Kim and Khloé told how she woke partner Scott up at seven o'clock after taking a positive pregnancy test to share the news.
And Kourtney was so excited, she couldn't wait the traditional amount of time before sharing it with the world.
'Now I'm nine weeks along,' she told the magazine. 'You're supposed to wait 12 weeks to tell people, but I feel confident.'
In an episode of Keeping Up With the Kardashians in July, Kourtney was seen clashing with mother Kris Jenner after she mentioned that she and Scott were considering trying for another baby.
While their first child Mason was a happy surprise, the family matriarch is adamant that the couple should be married before thinking about expanding their family.
In the episode, Kourtney is insistent that she will marry if and when she chooses, and admits the reason she is hesitant to walk down the aisle is because she doesn't want her children to go through a parents' divorce they way she did as a child.
Kourtney Kardashian has revealed that she is just nine weeks into her pregnancy with second child to her partner Scott Disick. The couples son Mason, turns two on December 14.