Katy Perry, Katheryn Elizabeth Hudson

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.
• 2010–present: Teenage Dream
Perry appeared as a guest judge alongside Simon Cowell, Cheryl Cole and Louis Walsh during the Dublin audition stage of the seventh series of the British television show The X Factor on June 28, 2010 (later televised on August 28). She was one of the many celebrities chosen to fulfil the role of judge whilst Dannii Minogue was on maternity leave. She later returned to the show on October 17 to perform "Firework". Perry's second mainstream studio album was titled Teenage Dream and was released in August 2010. The first single from the album was titled "California Gurls". The single peaked at number one on the Billboard Hot 100 and was the fastest rising single from a Capitol Records artist since Bobbie Gentry's "Ode to Billie Joe" in 1967. The cover art for Teenage Dream is a painting by Will Cotton in which depicts Perry lying naked on clouds of cotton candy; resembling the shots of Perry in the video for "California Gurls". The booklet of the physical edition of the album, in keeping with the theme of cotton candy, has a cotton candy scent. The album's second single "Teenage Dream" was released in July 2010. "Firework" is the album's third single.