She announced the good news Monday via Twitter.
"I'm officially Mrs. Blackstock :) We got married yesterday at Blackberry Farms in TN, the most beautiful place ever!" she wrote, including the photo above.
The bride wore an Alice Temperley gown on her special day, according to Us Weekly. More surprisingly, Clarkson, who's getting her pilot's license, flew the couple in for the ceremony, the mag said. Talent manager Blackstock, 36, was going to fly them back out afterward.
A small group of friends and family attended, E! News reported, including Blackstock's children from his first marriage.
Clarkson, 31, who announced her engagement last December on Twitter, had been planning elaborate nuptials up until August, when she pulled the plug. Not on the wedding, mind you, just on the crazy celebration surrounding it.
"We are so busy that we finally just came to terms the other night and were like, 'So, we change our minds and we want to elope.' We just got so overwhelmed by it -- all the decisions," Clarkson told People at the time.
With Blackstock comes a 12-year-old daughter, Savannah, and 6-year-old son, Seth, Clarkson told Rachael Ray earlier this month, and their presence seems to have had a broody influence on the singer.
"I never wanted kids," she said, "and now I want babies. ... I really want to make the time."