AC/DC frontman Brian Johnson has confirmed that an unidentified member of the band is suffering from a "debilitating illness," leaving the band's future "up in the air at the moment." However, he also indicates the band hasn't decided to say goodbye just yet.

"I wouldn't like to say anything either way about the future," he tells the Telegraph. "I'm not ruling anything out. One of the boys has a debilitating illness, but I don't want to say too much about it. He is very proud and private, a wonderful chap. We've been pals for 35 years and I look up to him very much." The band have plans for a recording session in May, but what happens next is unknown.

The ailing member is reportedly rhythm guitarist Malcolm Young, older brother of AC/DC's lead guitarist Angus Young. That's put in jeopardy plans for a huge 40th anniversary tour, in which AC/DC was hoping to play 40 concerts in 40 different venues. "That would be a wonderful way to say bye bye," Johnson adds. "We would love to do it. But it's all up in the air at the moment."

Malcolm Young's health issues were first reported by friend Mark Gable, who said the 61-year-old is "unable to perform anymore" -- perhaps because of a stroke. Rumors of their retirement immediately followed, despite the fact that AC/DC has already survived the death of a key member when former singer Bon Scott passed unexpectedly in 1980. Johnson has fronted AC/DC ever since.

"We are definitely getting together in May in Vancouver," Johnson confirms. "We're going to pick up some guitars, have a plonk, and see if anybody has got any tunes or ideas. If anything happens, we'll record it."

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