one 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 number one Mainstream Rock hits and a number one adult contemporary radio hit in the US. This was the band's third of four number one singles on the Mainstream Rock chart. The song spent five weeks at number one in Australia and also hit the top of the charts in Canada, Ireland, New Zealand, Norway and Sweden, while peaking at number two in Switzerland and South Africa. The song has received positive retrospective reviews from critics, with Bret Adams of AllMusic writing: "It's not hard to see why it became Foreigner's first number one single. Its dreamy, hypnotic feel is due in part to Lou Gramm's soulful lead vocals and the New Jersey Mass Choir's background vocals." The song was also issued as a 12-inch single with a longer running time of 6:23. This version contains a slightly longer intro and an extended vocal chorus/fadeout ending. The single's B-side, "Street Thunder (Marathon Theme)," is an instrumental track originally appearing on The Official Music of the XXIII Olympiad – Los Angeles 1984 and later on the band's 2-CD compilation Jukebox Heroes: The Foreigner Anthology (2000). Soon after Foreigner's single topped the charts, the New Jersey Mass Choir released its own similar-sounding version of the song on an album also titled I Want to Know What Love Is. The choir's single peaked at number 37 on the then-Hot Black Singles chart and number 12 on the Hot Dance Music/Maxi-Singles Sales chart. "I Want to Know What Love Is" was ranked as the number four Billboard Hot 100 single of 1985. It was the band's third platinum single in the US and their first and only gold single in the UK. It was certified platinum in the UK in 2020. Jones has rated it as one of his 11 favorite Foreigner songs. Originally consisting of three verses, a pre-chorus and a chorus, the song was extended with a bridge written by original songwriter Mick Jones specifically for Tina Arena's cover in 1998. Personnel Foreigner Lou Gramm – lead vocals Mick Jones – keyboards, synthesizers, backing vocals Rick Wills – bass, backing vocals Dennis Elliott – drums Guest Musicians Tom Bailey – synthesizers Don Harper – backing vocals Jennifer Holliday – backing vocals and arrangements New Jersey Mass