He'd already suggested the follow-up to 2008's Death Magnetic wouldn't be released until 2015, although he'd also said work would begin in the coming weeks.

Ulrich tells La Viola "We've got some good ideas. Our biggest problem is not the ideas, our biggest problem is time," he said. "Metallica is busier than ever - it just seems like there's more and more going on and the days get shorter and shorter.