"Teenage Dream" is a song by American singer Katy Perry. It was released as the second single from her third studio album of the same name on July 23, 2010. Perry and Bonnie McKee wrote many songs with youthful themes in mind, but they were rejected by producers Benny Blanco and Dr. Luke. Blanco showed them The Teenagers' single "Homecoming", and McKee imagined "Teenage Dream" as a throwback song to the euphoric feelings of being in love as a teenager. They met with Max Martin in Perry's hometown of Santa Barbara, California and started writing the track at Playback Recording Studio, which Perry later described as a pure moment for her. After Perry recorded her vocals, McKee presented her idea and the chorus was rewritten. Perry also described the song as reminiscent of her youth while contemplating her future marriage to Russell Brand.

Musically, "Teenage Dream" is a mid-tempo pop song with a retro sound. It is styled in the genres of power pop and electropop, while taking influence from other genres such as disco and pop rock. Perry starts the song in a high-pitched voice while her vocals grow stronger as the song progresses. Lyrically, "Teenage Dream" discusses being with a lover who makes one feel young again. The song has topped the Billboard Hot 100, becoming Perry's third number-one single on that chart, and her second consecutive number-one single after "California Gurls". "Teenage Dream" has been certified seven times platinum in the United States, as well as receiving platinum and multi-platinum certifications in other countries.

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