Metallica are "deep into the songwriting" for their new album, Lars Ulrich has revealed.
Following the release of their ninth record Death Magnetic in 2008, the drummer said the heavy metal rockers are already hard at work on their 10th album.
He told Rolling Stone: "We're going through the grind. We're in there doing riffs and putting them into songs. We don't really write one song and then show up the next day and do another one. We just work on riffs and sections, connecting riffs and tempos and moods."
The 50-year-old musician added that they have been working on the record "off and on" for almost a year and plan to reunite in the studio in May.
"We're going to start talking about who is going to produce the album. We haven't started recording yet. But we are deep into the songwriting part of it," he said.
Metallica, who starred in their own 3D concert film Metallica: Through The Never in 2013, will headline at Sonisphere Festival on July 6 in Knebworth.