The reality star and her ex-boyfriend, Canadian-American basketball player Tristan Thompson, welcomed their second child via surrogate, a source close to Kardashian told CNN.
No name for the baby boy has yet been shared.
The former couple are also parents to 4-year-old daughter True.
The couple had a tumultuous, on-and-off relationship marred by several cheating scandals. In January, Thompson confirmed he had welcomed a son with fitness model Maralee Nichols.
But Kardashian, 38, has expressed her commitment to co-parenting with Thompson and her desire to grow her family. She documented her efforts to conceive a second child through IVF and fertility assistance in “Keeping Up with the Kardashians.”