Khloé, who is 8 months pregnant, is expected to give birth in late March/early April.
The 33-year-old waited until she was 5 months pregnant to confirm the news with fans, writing in an emotional Instagram post:
"My greatest dream realized! We are having a baby! I had been waiting and wondering but God had a plan all along. He knew what He was doing. I simply had to trust in Him and be patient. I still at times can't believe that our love created life!
"Tristan, thank you for loving me the way that you do! Thank you for treating me like a Queen! Thank you for making me feel beautiful at all stages! Tristan, most of all, Thank you for making me a MOMMY!!! You have made this experience even more magical than I could have envisioned! I will never forget how wonderful you've been to me during this time! Thank you for making me so happy my love!"
We can't wait to meet baby Thompson!