To their fans, AC/DC are the absolute epitome of hard rock, an electrifying experience both on stage and in the studio.
One of the most successful rock groups of all time, the band had previously intimated that preparations were under way for a new album or tour - ostensibly to toast the anniversary of their 1973 foundation or their 1975 debut album.
Since then, though, speculation has mounted that the group are suffering from a few difficulties. Now an Australian commentator has broken cover, with Peter Ford intimating that AC/DC could be set to retire.
The reasons are as yet unclear, although reports in Australia - such as that on ACA - are linking rhythm guitarist Malcolm Young with poor health.
If so, it would be a sad loss - AC/DC remain a thrilling, once-in-a-lifetime live experience, while 2008's 'Black Ice' album saw the Australian band return to the feral boogie of their early material.
More on this as it happens.