"Hot n Cold" is a song by American singer Katy Perry. The song was written by Perry, Dr. Luke, and Max Martin and produced by Luke and Benny Blanco for her second studio album, One of the Boys (2008). It was released as the album's second single on September 9, 2008. The lyrics address an unstable romantic relationship caused by a partner's mood swings. The song reached number three on the Billboard Hot 100, becoming Perry's second consecutive top five single, following "I Kissed a Girl". It also became Perry's second top five single in the United Kingdom, Australia, Ireland and New Zealand, and topped the charts in Finland, Germany, Canada, Norway, and Denmark, among others. "Hot n Cold" has sold over 5.8 million copies in the US, making it one of Perry's highest-selling singles in the nation. To promote "Hot n Cold", Perry marked the song's live debut with a performance on NBC's Today. She also performed the song at the 2008 MTV Europe Music Awards, which she hosted. The song's music video, which was directed by Alan Ferguson, was released on October 1, 2008, and features Perry as a bride who is about to marry her fiancé, who experiences a daydream in which she pursues him after he flees from the wedding. "Hot n Cold" was nominated for the Grammy Award for Best Female Pop Vocal Performance at the 52nd Annual Grammy Awards. Perry has also performed the song on all of her tours: Hello Katy Tour, California Dreams Tour, Prismatic World Tour and Witness: The Tour.