Blabbermouth.net said the musicians have confirmed they have begun thinking about the follow up to Death Magnetic.

"We're not going to start recording, we're going to start writing," drummer Lars Ulrich said. "We don't know what's inspiring us right now," continued frontman James Hetfield. "I've been itching to write for a long time — all of us have — so there's lots of ideas."

Still, Metallica has some inkling of where they're headed, reports Rolling Stone. "[There are] lots of riffs to jam on, and that's pretty exciting for us," bassist Robert Trujillo added.

But fans shouldn't hold their breath – not even the band knows what the process will be like.

"It could go very quick, it could take a long time; we have no idea. That's the beauty of the artform," said Hetfield. Though Metallica recorded Lulu, their collaborative album with Lou Reed, in 10 days, the group isn't sure how the experience will impact their next record.

"I think everything we do affects the next thing somehow. We don't know how that will show up. That is another way of writing," Hetfield said.

"I think it gave us confidence that we can go in and trust a little more of the moment. There's another side of this that is complete obsessive and perfectionist. So finding a balance is key.”