The band last week released 17th album Rock Or Bust, their first without mainman Malcolm Young, who was forced to retire as a result of dementia. Johnson tells ABC Australia:

"To me it was always up to Angus. He's one of these two men who made riffs that nobody else made, since they were in school. I really thought it might not happen. If Angus turned round and said, 'I can't do it without Malcolm,' I would have understood."