The Righteous Brothers became stars thanks to two defining songs - Unchained Melody and You've Lost That Lovin' Feelin'.
The duo were not the first to take Unchained Melody into the charts
Both were produced by recording wizard Phil Spector, famed for his booming, echoing "wall of sound" technique, in the 1960s.
You've Lost That Lovin' Feelin', released in 1964, was their first major hit, and some music critics hold it up a lynchpin of the wall of sound technique that made Spector a legend.
But despite having two enormous hits, The Righteous Brothers were caretakers, rather than owners, of the songs that brought them fame.
And the songs have spawned a legion of cover versions - from the sublime to the ridiculous.
Unchained Melody versions in the UK charts, 20 June 1955
The Les Baxter Orchestra
Unchained Melody, according to the US music website Allmusic, has been released on record 697 times.
It was not written by the duo, but by songwriters Hy Zanet and Alex North, and was based on a little-known film called Unchained, about a California ''honour prison".
The song was sung on the soundtrack by a singer called Al Hibbler, and was nominated for the Academy Awards in 1955, as well as being recorded orchestrally.
Both versions of the song were released in 1955, with the orchestral version - by The Les Baxter Orchestra - going to number one, and Hibbler's version peaking at number three.
Meanwhile, music writer Terry Staunton told BBC News Online, Unchained Melody madness had taken hold in the UK.
"There were no less than four versions of Unchained Melody in the UK charts in June 1955: Al Hibbler, The Les Baxter Orchestra, our own Jimmy Young - and Liberace," Mr Staunton said.
The list of artists who have since covered the track include family favourite Bing Crosby, rock 'n' roll icon Elvis Presley and soundtrack king Henry Mancini (best known for Breakfast at Tiffany's Moon River).
Cruise sang You've Lost That Lovin' Feelin' in Top Gun
And it also includes French pianist Richard Clayderman, Irish flautist James Galway, whistling lounge singer Roger Whittaker, and Romanian "master of the pan flute" Gheorghe Zamfir.
The Righteous Brothers would belatedly take the song to number one in the UK in 1990, hot on the heels of the movie Ghost.
Mr Staunton said the romantic drama, starring Demi Moore and Patrick Swayze, was almost called Unchained Melody because the producers had already chosen the song for the soundtrack.
Interestingly, Mr Staunton said, Hatfield was the only Righteous Brother to actually sing on the duo's original version of the song.
It was re-recorded - with Bill Medley - for the soundtrack.
Roberson Green and Jerome Flynn, two of the stars of the ITV series Soldier, Soldier, took the song to number one in 1995 in record-breaking style.
They also covered...
Peter Sellers (above, Unchained Melody)
Stevie Wonder (You've Lost That Lovin' Feelin')
Heart (Unchained Melody)
Hall and Oates (You've Lost That Lovin' Feelin')
Roger Whittaker (Unchained Melody)
The Human League (You've Lost That Lovin' Feelin')
Robson and Jerome's version was the biggest-selling - it sold more than 1.8m copies. At the time it was one of the 10 biggest-selling singles in the UK.
Most recently, Pop Idol runner-up Gareth Gates took the song to number one again when it was his debut single earlier this year.
As for You've Lost That Lovin' Feelin' - the brothers' first hit -
Mr Staunton said, there were two other versions to grace the UK charts.
In 1965 Liverpool's own Cilla Black took the track to number one, while in 1975 Kojak actor Telly Savalas had a minor hit with his version.
Prior to Don't You Want Me? fame, Sheffield electro-pop group The Human League also recorded the song.
"This was back in the days before the girls joined the group, when they were electronic and experimental," said Mr Staunton.
"I think they recorded it to make up the numbers on a John Peel session for the BBC."
He said the song had been written by Spector - and his songwriting cohorts Barry Mann and Cynthia Weil - as a form of studio experimentation.
The song has not been as widely covered as Unchained Melody, but Phil Collins, synth pop kings Erasure and blue-eyed soul torchbearers Hall and Oates have all given it new life.
An ear-curdling rendition by Tom Cruise even featured in a bar-room scene in 1980s blockbuster Top Gun.
A recent Channel 4 list of worst TV moments included Paul Shane - Ted Bovis from TV's Hi De Hi - warbling his way through a version on a daytime TV show.
"In some people's hands the song is an evergreen pop classic," Mr Staunton said.
"In other hands it is one of the most frightening moments of television."