"Telephone" is a song written and performed by Lady Gaga. It was released from her third extended play (EP) and second major release The Fame Monster (2009). The song, featuring American R&B singer Beyoncé Knowles, was written by Gaga and Rodney Jerkins. Inspired by her "Fear of Suffocation Monster", Gaga explained that the lyrics portray herself preferring the dance floor instead of answering her lover's phone call and noted that the telephone addressed in the lyrics of the song is, in reality, a person telling her to continue working harder. Musically, "Telephone" consists of an expanded bridge, verse-rap and an epilogue where the voice of an operator announces that the phone line is unreachable. Knowles appears in the middle of the song, singing the verses in a rapid-fire way, accompanied by double beats.

A critical success, most contemporary critics frequently noted "Telephone" as a stand-out track from The Fame Monster and it was Grammy-nominated for Best Pop Collaboration with Vocals in 2011. "Telephone" charted in a number of countries due to digital sales following the album's release, namely in the United States, Australia, Canada, the Netherlands, New Zealand, Sweden and Hungary. The song was particularly successful in Europe where it reached the top of the charts in Belgium, Denmark, Hungary, Ireland, Netherlands, Norway and the United Kingdom. According to the International Federation of the Phonographic Industry, the single sold 7.4 million digital copies worldwide in 2010.

Stefani Joanne Angelina Germanotta (/ˈstɛfəniː dʒʌrməˈnɑːtə/ STE-fə-nee jurr-mə-NAH-tə; born March 28, 1986), known by her stage name Lady Gaga, is an American singer and songwriter. Born and raised in New York City, she primarily studied at the Convent of the Sacred Heart and briefly attended New York University's Tisch School of the Arts before withdrawing to focus on her musical career. She began performing in the rock music scene of Manhattan's Lower East Side, and was signed with Streamline Records by the end of 2007. During her employment as a songwriter for the record company, her vocal abilities captured the attention of recording artist Akon, who signed her to his label Kon Live Distribution.

Lady Gaga came to prominence as a recording artist following the release of her debut album The Fame (2008), which was a critical and commercial success that topped charts around the world and included the international number-one singles "Just Dance" and "Poker Face". After embarking on the The Fame Ball Tour, she followed the album with The Fame Monster (2009), which spawned the worldwide hit singles "Bad Romance", "Telephone" and "Alejandro". The album's success allowed her to embark on the eighteen-month long Monster Ball Tour, which later became one of the highest-grossing concert tours of all time. Her most recent album Born This Way (2011) topped the charts of most major markets and generated more international chart-topping singles, including "Born This Way", "Judas" and "The Edge of Glory". Besides her musical career, she involves herself with humanitarian causes and LGBT activism.