Metallica's James Hetfield has been busy penning new music and revealed he's been inspired by Sir Elton John.

The heavy metal titans performed the music legend's hit medley, 'Funeral for a Friend/Love Lies Bleeding', when the 'Tiny Dancer' hitmaker and his longtime songwriting partner Bernie Taupin received the Library of Congress Gershwin Prize for Popular Song.

And the frontman has admitted the experience "challenged" him and it's seeping into the songwriting he's been doing of late.

Speaking 'The Metallica Report' podcast, he spilled: “The time off has been pretty fantastic but, at the same time, I missed playing with the guys. And I let them know, ‘Man, I miss jamming with you guys!’

“We’ve done a few things here and there.

“The Elton John thing [covering Funeral For A Friend/Love Lies Bleeding on TV in April] was so fantastic. Had a blast there. Elton, what a beautiful soul.”

The 'Nothing Else Matters' rocker loves nothing more than escaping to his little makeshift music studio in his basement to work on new tunes and admits playing the guitar every day is "like breathing" for him.

He shared: “[I’ve] been doing some skiing, getting up on the mountain – there’s been tons of snow in Colorado, where we’re at, so a good snow season – and writing loads of music.

“[I’ve been] playing guitar pretty much every day. I have to. It’s like breathing."

Hetfield says he's always full of ideas and music is "an escape" for him.

He said: “I’m so grateful it doesn’t shut off.

“Whether it’s an escape from life or whatever it is, I love my little music room basement. I’ve got a computer, a few guitars and a little rig set up. It is my soul-nourishing place, to go in there and just play and write. Not so much practicing, it’s just writing."

He continued: “There’s always ideas. I get inspired [by] all kinds of different music, listening to it. Even the Elton John thing, hanging out with Elton and Bernie Taupin challenged me.

“Watching [2019 John biopic] Rocketman and seeing how they wrote – Elton is such a visionary in the way that Bernie sets a set of lyrics, a poem, in front of him and he sees the music just appearing, which is bizarre to me. I’m more of the old Tony Iommi way, where, ‘Here is the riff, and we build around the riff,’ you know?”

Metallica's last studio album was 2023's juggernaut '72 Seasons'.