MusicXML scores for euphonium by Katy Perry

Katheryn Elizabeth Hudson (born October 25, 1984), known professionally as Katy Perry, is an American singer, songwriter, and television personality. She is known for her influence on modern pop music and her camp style, being dubbed the "Queen of Camp" by Vogue and Rolling Stone. At 16, Perry released a gospel record titled Katy Hudson (2001) under Red Hill Records, which was commercially unsuccessful. She moved to Los Angeles at 17 to venture into secular music, and later adopted the stage name "Katy Perry" from her mother's maiden name. She recorded an album while signed to Columbia Records, but was dropped before signing to Capitol Records.

Perry rose to fame with One of the Boys (2008), a pop rock record containing her debut single "I Kissed a Girl" and follow-up single "Hot n Cold", which reached number one and three on the U.S. Billboard Hot 100 respectively. The disco-influenced pop album Teenage Dream (2010) spawned five U.S. number one singles—"California Gurls", "Teenage Dream", "Firework", "E.T.", and "Last Friday Night (T.G.I.F.)"— the only album by a female singer to do so. A reissue of the album titled Teenage Dream: The Complete Confection (2012) subsequently produced the U.S. number one single "Part of Me". Her empowerment-themed album Prism (2013) had two U.S. number one singles, "Roar" and "Dark Horse". Both their respective music videos made Perry the first artist to have multiple videos reach one billion views on Vevo and YouTube. The electropop album Witness (2017) featured themes of feminism and a political subtext, while Smile (2020) was influenced by motherhood and her mental health journey. Afterwards, she embarked on her Las Vegas concert residency titled Play (2021–2023), receiving critical acclaim and commercial success.

Perry is one of the best-selling music artists of all time, having sold over 143 million records worldwide. All of her major-label studio albums have individually surpassed one billion streams on Spotify. She has nine U.S. number one singles, three U.S. number one albums, and the second-most U.S. diamond certified singles for any female artist (4). She has received various accolades, including a Billboard Spotlight Award, four Guinness World Records, five Billboard Music Awards, five American Music Awards, a Brit Award, and a Juno Award. Forbes ranked Perry as the world's highest-paid female musician in 2015 and 2018, and as one of the wealthiest musicians with an estimated net worth of $350 million. Outside of music, she released an autobiographical documentary titled Katy Perry: Part of Me in 2012, voiced Smurfette in The Smurfs film series, and launched her own shoe line Katy Perry Collections in 2017. Perry served as a judge on American Idol for seven seasons from 2018–2024. She is also the second most-followed woman and the sixth most-followed person on Twitter, with over 106 million followers.