Rock Or Bust was released earlier this month. It's their first title without mainman Malcolm Young, who had to retire due to his dementia. The future of drummer Phil Rudd is in doubt as a result of his current legal issues.

In a recent interview just released by the BBC, Johnson says: "I've got to stick my hand up and tell the truth - I went to Vancouver with the boys and I hadn't sung a song in anger in five and a half years.