Cavallari, 25, is engaged to Chicago Bears quarterback Jay Cutler, 29.
"We are thrilled to welcome Camden Jack Cutler into the world," Cavallari tweeted. "He was born this morning weighing 7 lbs., 9 oz. Everyone is doing great!"
Cavallari is best known for her work on TV's "Dancing with the Stars" and "Laguna Beach."
Easer Egg Roll brings thousands to White House
Moore to attend retreat in to avoid Kutcher's wedding