"Unchained Melody" is a 1955 song with music by Alex North and lyrics by Hy Zaret. North wrote the music as a theme for the little-known prison film Unchained (January 1955), hence the song title. Todd Duncan sang the vocals for the film soundtrack. It has since become a standard and one of the most recorded songs of the 20th century, most notably by the Righteous Brothers. According to the song's publishing administrator, over 1,500 recordings of "Unchained Melody" have been made by more than 670 artists, in multiple languages.

In 1955, three versions of the song (by Les Baxter, Al Hibbler, and Roy Hamilton) charted in the Billboard Top 10 in the United States, and four versions (by Al Hibbler, Les Baxter, Jimmy Young, and Liberace) appeared in the Top 20 in the United Kingdom simultaneously, an unbeaten record for any song. The song continued to chart in the 21st century, and it was the only song to reach number one with four different recordings in the UK until it was joined by Band Aid 30's "Do They Know It's Christmas?" in 2014.

The version by Robson & Jerome is notable as the best-selling single of 1995 in the UK. It also launched the singing career of Robson & Jerome, and became the biggest hit in the UK for Simon Cowell, marking his beginning as a significant figure in the music industry.

In November 1994, in an episode of the UK television drama series Soldier Soldier, characters Dave Tucker and Paddy Garvey, portrayed by actors Robson Green and Jerome Flynn respectively, performed "Unchained Melody" as an impromptu duo, The Unrighteous Brothers, after the entertainment failed to appear for a friend's wedding. Their performance triggered a strong response from the audience who attempted to find a recording of the song that was then unavailable. Simon Cowell was alerted to the interest shown by the public, and pursued the two reluctant actors for the next four months to record the song, to the extent that Robson Green threatened legal action to stop Cowell harassing them. The actors were eventually persuaded to sign a recording contract with Cowell and record a Righteous Brothers-type version of the song as a duo. The recording was produced by Mike Stock and Matt Aitken. It was released as a double A-sided single with "White Cliffs of Dover", a popular song during World War II, included in recognition of the 50th anniversary of VE day, the date of the single release.The video released for "Unchained Melody" also incorporated clips from the 1945 film Brief Encounter.

Their recording immediately reached number 1 in the UK, selling 314,000 copies in its first week, at that time the fastest-selling debut single in UK chart history. It stayed at the top of the chart for seven weeks. It became the best selling single of 1995, and one of the country's all-time biggest-selling singles (No. 9 in November 2012), with 1.87 million copies sold. The self-titled album they released later in the year also became the best-selling album of 1995. Although the duo decided to quit the following year, they would eventually sell 7 million copies of albums and 5 million copies of the 3 singles released.