Robert Plant has admitted he finds it hard to find the "words" to pen new lyrics.

The former Led Zeppelin frontman penned the lyrics in the iconic rock band, but these days, he struggles to know what to write about.

He told Rolling Stone: “I’ve got a Tascam digital recorder, and I sing, and I put the vocals through a guitar pedal, and then I record them on that over there, and it sounds great. Why bother to go to the studio? But I can’t find words. This is a very difficult time to try and wax lyrical out there.”

However, he's vowed to keep making music.

He added: “For me, the continuum must keep going. Today, I was pulling all my lyric books out and going, ‘Gotta get the groove back. I’ve got something to say.’ So yeah, I’m going to keep going — as long as they’ve got effects machines that make me sound good.”

Elsewhere, the 75-year-old musician - who is set to embark on a tour with his collaborator Alison Krauss this summer - admitted it was "cathartic" performing Led Zeppelin classic 'Stairway To Heaven' again.

Plant jumped onstage in October at a charity concert for The Cancer Platform at Soho Farmhouse in Oxfordshire, which was hosted by Duran Duran's Andy Taylor, who has been undergoing treatment for stage 4 prostate cancer.

Before then, the last time he performed the 1971 hit was when the band performed at The O2 in London in 2007.

He said: "It was cathartic. People go, 'Oh, that's good. He never was going to do that.' But I didn't really do it! I just blurted it out. 'Cause it's such an important song to me for where I was at the time and where I was with Jimmy [Page] and with John [Paul Jones] and Bonzo [John Bonham]. So on that night, it was what it was. It was a trial by fire, but I felt better at the end than at the beginning."

Asked about it potentially being his last performance of the song, he said: "Yeah, I think you're probably right. I haven't got around to doing the ice-skating rinks in Finland yet with a small orchestra. [Laughs] So I don't think I'll be doing that, but I don't know. Who knows? Something could change somewhere. Spirit and heart could come back in the soul. It's a long song. Who can remember all those words?"