What began as a joke is now serious business for Miranda Sings, the YouTube character created by California native Colleen Ballinger. Since her first video ("Free voice lesson") went viral unexpectedly a few years ago, Miranda Sings has become an Internet sensation, racking up millions of page views and performances around the country. On July 20, Ballinger will be here, leading a master class for kids at the Boston Children's Theatre's summer residence at the Governor's Academy in Newbury. She'll also perform the next night at the Art House in Provincetown. When we reached her Tuesday in Long Beach, Calif., the 25-year-old Ballinger said her character was inspired by a few of her less-talented college classmates who liked to shoot video of themselves singing in their bedrooms. "As a vocal performance major, I went to school with a lot of singers who were cocky and not very nice," she said. "It was sort of a joke with my friends, but people seemed to enjoy this horrible character." Viewers quickly discovered she wasn't real, but it didn't matter: Miranda Sings was so bad, she was good. (Her parody of Katy Perry's "California Gurls" video logged 1 million views on YouTube in a week, and her parodies of "Sexy and I Know It" and Beyoncé's "Single Ladies" also generated more than 1 million hits.) Miranda Sings will do her shtick for the BCT kids and then Ballinger will talk about the importance of social media in selling yourself. Asked if she's frustrated that her annoying, untalented alter ego is the one that's famous, Ballinger sighed. "I love and enjoy vocal performance," she said, "but I also have a huge passion for comedy and improv. I'm grateful to Miranda for giving me a career."