Katy Perry, Katheryn Elizabeth Hudson

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.
On May 16, 2009, Perry performed at the opening ceremony of the annual Life Ball in Vienna, Austria. In June 2009, lawyers acting for Katy Perry opposed the recent trademark of Australian fashion designer Katie Perry who uses her own name to market loungewear. Some media outlets reported this as a lawsuit, which Katy Perry has denied on her blog. Katie Perry the designer reports on her blog that at a hearing with IP Australia on July 10, 2009, the singer's lawyers withdrew their opposition to the trademark. During the summer of 2009 Perry filmed a cameo appearance for Get Him to the Greek; her scene, in which she kisses her future fiancé Russell Brand was cut, and does not appear in the final film. Discussing the issue with MTV, Perry hypothesized there may have been some fear that seeing the two make out would have taken viewers out of the experience. In 2009, Perry was featured on two singles: a remix of Colorado-based band 3OH!3's song "Starstrukk" in August (the idea for the collaboration came after Perry's tour that featured 3OH!3 as the supporting act). The song was released over iTunes on September 8, 2009; and "If We Ever Meet Again", the fourth single off Timbaland's album Shock Value II in December. In October 2009, MTV Unplugged revealed that Perry was one of the artists to perform for them, and that she would be releasing a live album of the performance, including two new tracks, "Brick by Brick" and Fountains of Wayne cover "Hackensack". The album was released on November 17, and includes both a CD and a DVD.