AC/DC frontman Brian Johnson has broken his silence about bandmate Malcolm Young's dementia battle, revealing he missed the guitarist in the studio while the band was recording new album Rock or Bust.

Young's condition forced him to exit the band earlier this year and he has been replaced in the line-up by his nephew Stevie Young, who Johnson insists was more than a suitable fill-in.

The British rocker tells Classic Rock magazine, "We missed Malcolm, obviously. Stevie was magnificent in his stead, but when you’re recording with this thing hanging over you, and your work mate isn’t well, it’s difficult. I’m sure he was rooting for us the whole time we were over in Canada."

Johnson reveals he wanted to call the band's new album Man Down as a tribute to Young, adding, "It’s from the heart... but some of the guys thought it might be a bit negative."