AC/DC’s Malcolm Young is seriously ill and will not perform live again, a friend and musical contemporary says.

Choirboys (of ‘Run to Paradise’ fame) frontman Mark Gable says he believes the 61-year-old founding guitarist is unable to perform anymore and will probably never record again.

Rumours have been swirling since Tuesday that AC/DC are preparing to announce they will be hanging up their guitars and school uniforms for the last time.

“That is true, Malcolm is sick,” Gable told ABC radio on Wednesday.

“From what I understand, and it’s even been confirmed in part by his son Ross (Young), that it would appear Malcolm is unable to perform anymore.

“It’s not just that he is unwell, it’s that it is quite serious. It will constitute that he definitely won’t be able to perform live.

“He will probably not be able to record.”

Gable and the Choirboys have been close to AC/DC for years.

In the early 1980s, they recorded their first self-titled album in the same studio the Australian hard rock band made their first five albums, after Angus and Malcolm Young’s older brother and Easybeats founder George Young heard their demo in Sydney.

Claims of AC/DC’s impending retirement were originally made in an email to Perth radio station 6PR by a person identified as “Thunderstruck”.

“My information is that Malcolm Young has moved himself and his family back to Australia, he’s very very ill and that AC/DC may well be history,” Thunderstruck told 6PR on Tuesday morning.

But Gable said Young’s illness may not necessarily stop the band from continuing with plans for their 40th anniversary tour and to record their first album since 2008’s Black Ice.

“There was speculation that they had this even tacit agreement that if no member currently was able to perform, DC would cease,” Gable said.

“However Alex Young’s son Stevie replaced Malcolm Young a few years back for a tour, and nobody knew the difference.”

AC/DC was formed by brothers Angus Young, now 59, and his brother Malcolm, who migrated from Scotland to Sydney when they were children, in 1973.

For more than three decades, the band has performed at sold-out concerts across the globe.

One of the group’s best-loved works is their successful and influential Back In Black album, which sold more than 22 million copies in the US. – AAP

IMAGE (left to right): AC/DC’s Cliff Williams, Malcolm Young, Angus Young and Brian Johnson together at the London world premier of the band’s ‘AC/DC: Live at River Plate’ DVD in 2011. It was possibly the guys’ last public appearance together. (Photo by Justin Ng)