"When Love Comes to Town" is the 12th song on U2's 1988 album, Rattle and Hum, where it was recorded at the historic Sun Studio in Memphis as a duet between U2 and B.B. King. It was released as the album's third single in 1989 and reached number 1 in the Irish Singles Chart, number 6 in the UK singles chart, number 10 in the Dutch Top 40 and number 2 in the US Mainstream Rock Tracks chart.

Little Richard is featured preaching, rapping in funky rhyme style, and singing background vocals amid Maceo Parker's saxophone playing on the extended "Live from the Kingdom Mix." The single contained two different versions of the Patti Smith song "Dancing Barefoot". The 7" and cassette featured the long version, while the 12" and CD contained the short version. While U2 has stopped playing it live since 1993, it continued to be featured in B. B. King concerts. During the Lovetown Tour concerts, this song would be played, usually along with "Angel of Harlem" and "Love Rescue Me", in an encore featuring B. B. and his band.

Like the song "Van Diemen's Land", this song originally featured an extra verse:

This verse was sung during the song's premiere in Fort Worth, Texas on U2's Joshua Tree Tour and does not appear in the studio version or subsequent live performances.

The debut performance took place on 24 November 1987 in Fort Worth, TX during the concert's encore and BB King joined U2 to perform the song. On 1989's Lovetown Tour, the song again featured during the encore and was played with BB King. It was played at 46 of the 47 shows; the only concert it missed was 18 December 1989 in Amsterdam, as the show concluded prematurely due to Bono suffering vocal problems.

...
Wikipedia