"I Want to Know What Love Is" is a power ballad by the British-American pop rock band Foreigner. It was released in November 1984 as the lead single from their fifth album, Agent Provocateur. The song hit number one in both the United Kingdom and the United States and is the group's biggest hit to date. It remains one of the band's best-known songs and most enduring radio hits, charting in the top 25 in 2000, 2001, and 2002 on the Billboard Hot Adult Contemporary Recurrents chart. "I Want to Know What Love Is" has continued to garner critical acclaim, and is listed as one of Rolling Stone Magazine's greatest songs of all time at #479. The song is also featured in a number of films.

Written and composed by Mick Jones, with an uncredited portion (somewhere between 5% according to Jones and 40% according to Gramm) by Lou Gramm, and produced by Jones and Alex Sadkin, "I Want to Know What Love Is" was the first single released from Foreigner's album Agent Provocateur (1984). The song features backing vocals from the New Jersey Mass Choir affiliated with the Gospel Music Workshop of America, Dreamgirls star Jennifer Holliday, and featured keyboard work by Thompson Twins frontman Tom Bailey. The choir also appears in the song's music video.

"I Want to Know What Love Is" reached #1 in the UK Singles Chart on January 15, 1985, displacing Band Aid's "Do They Know It's Christmas?", staying there for three weeks, and knocked Madonna's long-running "Like a Virgin" out of #1 on the Billboard Hot 100 on February 2, 1985. It was Foreigner's first and only pop chart topper in either country, although the band had four #1 Mainstream Rock hits and a #1 Adult Contemporary radio hit in the US. This was the band's third of four #1 singles on the Mainstream Rock chart. The song spent five weeks at #1 in Australia and also hit the top of the charts in Canada, Ireland, New Zealand, Norway, and Sweden, peaking at #2 in Switzerland and South Africa.

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