"One" is a song by American singer-songwriter Harry Nilsson from his 1968 album Aerial Ballet. It is known for its opening line "One is the loneliest number that you'll ever do". Nilsson wrote the song after calling someone and getting a busy signal. He stayed on the line listening to the "beep, beep, beep, beep..." tone, writing the song. The busy signal became the opening notes. A better-known cover version, recorded by Three Dog Night, reached number five on the U.S. Billboard Hot 100 in 1969 and number four in Canada. In 1969, the song was also recorded by Australian pop singer Johnny Farnham, reaching number four on the Go-Set National Top 40 Chart.

Three Dog Night version

Three Dog Night released One as the second single from their eponymous first album, with Chuck Negron performing the lead vocal. It became their first of seven gold records over the next five years. The original issue of the single version fades out about ten seconds before the final notes heard on the album version. Upon reissues by ABC Records and its successor labels, the label reverted to the album version which is heard on radio today. The song reached number five on the U.S. Billboard Hot 100 and spent three weeks at number two on the Cash Box Top 100. It also reached number four in Canada.

Chart performance

Weekly charts

Year-end charts

Certifications

Other versions

Many cover versions have been recorded. Among the most notable are: