Sledge died at home in Baton Rouge. Photo: BBC NEWS

Steve Green from talent agency Artists International Management Inc confirmed to the BBC that he died at his home in Baton Rouge, Louisiana, on Tuesday.

"He was one of my first acts, he was a terrific person and you don't find that in this business very often," said Green. "He was truly a standout."

Sledge had surgery for liver cancer in January 2014 but soon resumed touring.

Sledge's debut single When a Man Loves a Woman reached the top 10 twice in the UK and topped the US Billboard chart for two weeks in 1966, when it also got to number four in the UK chart.

During an interview for the the 2013 documentary Muscle Shoals, he recalled his first recording of it.

"When I came into the studio, I was shaking like a leaf. I was scared," he said, adding that it was the "same melody that I sang when I was out in the fields. I just wailed out in the woods and let the echo come back to me".

'Signed away the rights'

He told BBC Radio 6 Music's Craig Charles in a 2011 interview that he came up with the melody for When A Man Loves A Woman, but signed away the rights of the song to Calvin Lewis and Andrew Wright, because "I didn't know any better".

"I had the melody in my mind so I gave that song to them," he said, adding they then created the lyrics.

Sledge did not contest the agreement, saying: "I felt like if God fixed it in my mouth to give it to them I won't change anything about it.

"I'm satisfied with what I wrote but I cut my kids out of so much because I gave it to someone else - I just wasn't thinking."

BBC Radio 2 DJ Tony Blackburn was among those paying tribute on Twitter, and said: "Sad to hear that Percy Sledge has died. I wonder how many times I've played When A Man Loves A Woman. RIP."

Musician Bootsy Collins paid tribute on his Facebook page with the words: "Just lost another legend funkateers, Mr Percy Sledge."

Sledge performed at his induction into the Alabama Music Hall of Fame in March 2010

Paul Gambacini told the BBC that When a Man Loves a Woman was "one of the all time classic songs".

"This was the essence of soul, dripping with feeling. It never had a time, it was in a world of its own, so it was timeless," he added.

The track reached number two when it was re-released in the UK in 1987 after appearing in Oliver Stone's film Platoon, and was featured in several other films such as The Big Chill, The Crying Game and a 1994 Meg Ryan drama named after the song itself. It was also the soundtrack to a Levis advert in 1987.

'Transcendent moment'

It was the first US number one recorded at Alabama's Muscle Shoals studio, where Aretha Franklin and the Rolling Stones would later record.

The track also scored a first gold disc for Atlantic Records, whose executive Jerry Wexler called the song "a transcendent moment" and "a holy love hymn."

It remained Sledge's biggest hit and helped sustain a long touring career in the US, Europe and South Africa, averaging 100 performances a year. His other chart successes included Warm and Tender Love, It Tears Me Up and Take Time to Know Her.

The song found new life in 1991 when Michael Bolton's cover of the song topped the Billboard chart.

Before his music career, Sledge worked in the cotton fields around his hometown of Leighton in northwest Alabama, before taking a job as a hospital nurse in the early 1960s.

A patient heard him singing while he worked and recommended him to record producer Quin Ivy.

The singer was inducted into the Rock and Roll Hall of Fame in 2005 and was a member of the Alabama Music Hall of Fame and the Louisiana Music Hall of Fame.

He is survived by his wife and children.