Life Imitates Art: Katy may or may not have written "The One That Got Away" before her relationship with (and subsequent marriage to) Russell Brand, but it became eerily appropriate that he filed for their divorce during the song's run as a single. He became the one that got away.
Her birth name is Katy Hudson, which she used on her first album. She changed it to Perry in order to avoid confusion with actress Kate Hudson.
In 2009 her lawyers opposed a trademark filed by Australian designer Katie Perry, which is the designer's real legal name. The claim was withdrawn.
No Export for You: A weird case involving "Prism." The album is packaged with seeds that fans are encouraged to plant. This created a problem in Australia, which is very protective of their unique ecosystems, as the seeds could easily become an invasive species. Australia has their own version of the album containing seeds for local flora, but international versions of the album (such as those purchased online), have been quarantines as a biohazard.