AC/DC have been forced to immediately postpone the latest leg of their 'Rock Or Bust Tour' in North America after it was revealed that lead singer Brian Johnson is on the verge of permanently losing his hearing.

The legendary rock group’s shows in the U.S. from March 4th in Atlanta until April 8th in New York have been delayed and will be rescheduled for later in 2016, after the band released a statement to the press saying that 68 year old Johnson had been “advised by doctors to stop touring immediately or risk total hearing loss.”

Whenever the ten shows in question are eventually re-arranged, they will “likely [be] with a guest vocalist”, prompting concerns that Johnson may be effectively forced into retirement as he battles this health problem.

Brian JohnsonBrian Johnson has been the lead singer of AC/DC since 1980

“More information regarding these rescheduled shows to come,” the band's announcement says. “Current ticket holders can hold on to their tickets for the rescheduled dates or receive a refund at point of purchase.”

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It’s been a torrid time for the heavy rock titans over the last couple of years, with founding member and rhythm guitarist Malcolm Young retiring from the band in 2014 after being diagnosed with dementia. Later the same year, drummer Phil Rudd became embroiled in a legal battle after he was accused of threatening to kill a former employee.

It also means that lead guitarist Angus Young is the only original member, and now the only one of the ‘classic’ AC/DC line-up, left still playing. This current tour, in support of 2014’s album Rock Or Bust, began back in April 2015.

Brian Johnson took over lead vocals in 1980, after the sudden death of the group’s first full-time singer Bon Scott. He has openly discussed his hearing difficulties in the recent past, telling radio host Howard Stern in 2014 that it was his love of motoring, not rock music, that was to blame for his loss of hearing.

More: Phil Rudd, AC/DC drummer, sentenced to 8 months home detention