The Since You've Been Gone singer has announced she will wed 35-year-old talent manager Brandon Blackstock, who popped the question last night after nine months of dating.
The 30-year-old star - who shot to fame after winning American Idol in 2002 - shared her joy with her fans on Twitter, writing: "I'm engaged!!!! I wanted y'all to know!! Happiest night of my life last! I am so lucky and am with the greatest man ever."
Kelly recently expressed her hopes that the couple would tie the knot even though they weren't yet engaged.
Last month, she said: "We are totally going to get married. We love each other. We are totally going to get married one day.
"I mean, he's got to put a ring on at some point. But I'll wait it out."