Katy Perry, Katheryn Elizabeth Hudson

She went on the next step of promoting the album, undertaking a two-month tour of radio stations. The album's official lead single, "I Kissed a Girl", was released on May 6, 2008. Perry's A&R, Chris Anokute, told HitQuarters the song and its controversial theme met with strong resistance at the label, "People said, 'This is never going to get played on the radio. How do we sell this? How’s this going to be played in the bible belt?'" Anokute said that they needed the support of one of the label's radio promoters to convince people to believe in the record otherwise Perry would have likely been dropped again. Capitol's SVP of Promotions Dennis Reese saw the vision and helped push the single on national radio. The first station to pick it up and take a chance was The River in Nashville. After playing it for three days they were innundated with enthusiastic calls. With the song climbing atop the charts, Perry embarked on the annual Warped Tour music festival, which her management used to "establish her as a credible performer and make sure she wasn't seen as just a one-hit wonder." The single was a commercial success, peaking at number one for seven weeks on the Billboard Hot 100. It has since become a major worldwide hit, topping charts in 30 countries, including Australia, Canada, and the United Kingdom. On June 12, 2008, Perry appeared as herself on the daytime soap opera The Young and the Restless, posing for the cover to the June 2008 issue of the fictional magazine Restless Style.
One of the Boys was released on June 17, 2008 to mixed critical reviews. The album has reached number nine on the Billboard 200, and has been certified platinum by the Recording Industry Association of America. Perry released her second single, "Hot n Cold", which became her second top three single in dozens of countries around the world, including the United States where it reached number three on the Billboard Hot 100, as well as topping the charts in Germany, Canada, and Denmark. After Perry wrapped up her appearance at the Warped Tour, she went on tours in Europe. She later launched her first headlining tour, the Hello Katy Tour, in January 2009. "I Kissed a Girl" earned Perry a nomination for Best Female Pop Vocal Performance at the 2009 Grammy Awards. Perry was nominated in five categories at the 2008 MTV Video Music Awards, including Best New Artist and Best Female Video, but lost to Britney Spears. She won Best New Act at the 2008 MTV Europe Music Awards, which she co-hosted, and Best International Female Artist at the 2009 BRIT Awards. On February 9, 2009, both "I Kissed a Girl" and "Hot n Cold" were certified three-time platinum by Recording Industry Association of America for individual digital sales of over three million. The Guinness Book of World Records recognized Perry in its 2010 version as the "Best Start on the US Digital Chart by a Female Artist," for having her first two singles sell over two million digital copies.
The Matrix's self-titled debut album, which features Perry, was later released via the team's label, Let's Hear It, during Perry's solo tour. When the release date was scheduled, "I Kissed a Girl" had been charting well. Matrix member Lauren Christy spoke to Perry about the decision, but she wanted to hold the release until the fourth single of One of the Boys had been dispatched. Despite their communication, The Matrix was released on January 27, 2009, via iTunes Store.
In December 2008, Perry apologized to British singer Lily Allen for remarks in which she called herself a "skinnier version" of her, saying she meant it as a joke. Allen retaliated and told a British radio station that she "happened to know for a fact that she (Perry) was an American version" of her because their record company needed "to find something controversial and 'kooky'" like her.