JoJo Siwa Defends 'Karma' Song, Explains How It Became Hers

Play video content TMZ.com JoJo Siwa has addressed the rumors she stole her new song from Miley Cyrus and Brit Smith ... telling TMZ she in no way swiped the single from anyone. We caught up with the 20-year-old outside Studio Siwa in Burbank, where she told us how she came into possession of her viral track, "Karma." As JoJo put it ... she was pitched the song -- which she defended as a very normal thing in the…