Sixto Rodriguez, the musician and subject of the documentary Searching for Sugar Man, has died aged 81.

The Detroit-born singer’s official website confirmed he died on Tuesday.

Rodriguez launched his career in 1967 but initially struggled to find success in his native US and was ultimately dropped by his record label.

However, his music gradually developed a cult following overseas, and his records enjoyed significant sales and airplay in South Africa and Australia.

Little was known about Rodriguez in the country despite his music being so popular, and false rumours had circulated that the singer had killed himself on stage in the 1970s.

But Rodriguez was in fact still alive and well and living in Detroit, having returned to a life of relative obscurity and construction work.

He was unaware of his popularity abroad, which partly stemmed from bootlegged copies of his album Cold Fact circulating in South Africa, where it been adopted as an unofficial soundtrack to youth protests against apartheid.

Despite his success in the country, Rodriguez only found out about his success in South Africa when his eldest daughter, Eva, came across a website dedicated to him in 1997 – when the internet was still in its relative infancy.

After contacting the website, Rodriguez went on his first South African tour in the late 1990s.

The Mexican-American singer and guitarist was playing sold-out shows in the country’s biggest arenas to thousands of fans and went on to perform a string of shows in Australia.

In 2012, the Oscar-winning Searching for Sugar Man saw two South African fans track Rodriguez down to see what had become of him.

The release of the documentary, which depicted the story of Rodriguez discovering his own fame overseas, saw his career enjoy another resurgence, and he began touring and recording once again.

The film prompted the two albums Rodriguez recorded in the early 1970s – Cold Fact and Coming From Reality – to become successful around the world four decades after their original release, and Rodriguez played festivals including Coachella and Glastonbury.

A statement posted on his official website read: “It is with great sadness that we at Sugarman.org announce that Sixto Diaz Rodriguez has passed away earlier today.

“We extend our most heartfelt condolences to his daughters – Sandra, Eva and Regan – and to all his family. Rodriguez was 81 years old. May His Dear Soul Rest In Peace.”

The musician’s cause of death was not announced.

Simon Chinn, who produced Searching For Sugar Man, described Rodriguez’s death as “such sad news”.

“He was a true legend, and it was an honour to know him,” he said. “What a privilege to be able to share his amazing story with the world. RIP Rodriguez – your music will live forever.”

South African musician David Scott, known as The Kiffness, said Rodriguez was a “legend with the most amazing life story”.

“In the US he lived in relative obscurity, but was hugely popular in here South Africa without him ever knowing until much later on,” he said.

“We will never witness a story like his in our lifetime again.”