Now, she's gearing up for a big performance at Rock the Red Kettle on Dec. 7. (Enter for a chance to win a trip to Los Angeles to attend the show in person!)
Check out the five things to know about the superstar singer.
5. She has her own workout DVDs. Ever wonder how Kelly keeps her killer bod, particularly her abs, in tip-top shape? The singer teamed up with celebrity fitness trainer Jeanette Jenkins and created a Sexy Abs workout in 2011, which focuses on building core strength, tone and flexibility. They then went on to release their second DVD, Sexy Abs: Cardio Sculpt in 2013, which is a total body workout.
4. She admitted to being jealous of Beyoncé in her single "Dirty Laundry" from her latest album Talk a Good Game. "Bird in a cage, you would never know what I was dealing with," she sang in the lyrics to the song. According to the New York Post, Kelly said that in spite of her past envy of Beyoncé though, Destiny's Child is "still very close." The trio not only reunited for their 2013 Superbowl performance, but they also came together for a song on Talk a Good Game called "You Changed."
3. Before she and Beyoncé formed Destiny's Child with original group members LeToya Luckett and LaTavia Roberson, they were both in a group called Girl's Tyme, and even appeared on Star Search.
2. According to Essence, she bought a home in Texas with her first major paycheck.
1. She may be known for her X Factor duties in the reality TV realm, but Kelly also served as a dance master on the Australian dance competition TV show Everybody Dance Now in Aug. 2012, in which she and Jason Derulo mentored, trained and challenged teams of dancers.