The 31-year-old singer said Tuesday on Twitter that she and husband Brandon Blackstock are expecting their first child together.
The original "American Idol" champion says the baby is the "best early Christmas present ever" in her tweet.
Clarkson's publicist, Mika El-Baz, later confirmed the information.
Clarkson and Blackstock were married last month. Blackstock is the son of Clarkson's manager, Narvel Blackstock, and the stepson of Reba McEntire. He manages country star and close Clarkson friend Blake Shelton.
Blackstock has two children from a previous marriage. No word on when the baby is due.