Speaking in an interview with the LA Times to publicise his current North American tour with Alison Krauss, Plant was asked about how his singing voice had changed over time.
"I know that the full, open-throated falsetto that I was able to concoct in 1968 carried me through until I was tired of it," Plant says. "Then that sort of exaggerated personality of vocal performance morphed and went somewhere else.
"But as a matter of fact, I was playing in Reykjavík, in Iceland, about three years ago, just before COVID. It was Midsummer Night and there was a festival, and I got my band and I said, 'OK, let’s do Immigrant Song.' They’d never done it before. We just hit it, and bang – there it was. I thought, 'Oh, I didn’t think I could still do that.'"
Reminded that fans would love to see him do the same with Led Zeppelin, Plant responded, "Going back to the font to get some kind of massive applause – it doesn’t really satisfy my need to be stimulated."
"I just go out and sing," he says. "I know a guy from a famous band that Alison’s quite friendly with – he’s gonna pour some sugar on me or something – who creates a complete hullabaloo backstage. I was back there one time and he was making such a bloody noise. I said, 'Why are you doing that?' He said, 'I’m warming up.' I said, 'Well, you won’t have anything left by the time you get there.'"
Alison Krauss sings on two tracks on Def Leppard's most recent album Diamond Star Halos, This Guitar and Lifeless.
Elsewhere in the LA Times interview, Plant and Krauss discuss the differences between British and American musicians, talk about their relationship outside music, and reflect on that fact that rock's pioneers are dwindling in number.
Plant and Krauss's US tour continues, while Plant also has Scottish and Irish dates lined up with Saving Grace, the band he fronts with Suzi Dian. Speaking to the BBC's Zoe Ball last November, Plant was asked about the likelihood of Saving Grace - who play covers of songs by the likes the Derek Trucks Band, Bob Dylan, Planxty, Moby Grape, Low, Donovan, Los Lobos, and Richard and Linda Thompson – recording an album.
“Saving Grace is a bunch of friends back from on the Welsh borders, Worcestershire," responded Plant, "and we do shows, very discreet, undercover shows. It’s a beautiful sound, a magnificent sound and it’s delicately tiptoeing its way to one day being yet another thing that we mustn’t know or talk about… so yes."
Robert Plant and Alison Krauss tour dates
Aug 20: Stateline Lake Tahoe Outdoor Arena at Harveys, NV
Aug 21: Berkeley Greek Theatre at UC Berkeley, CA
Aug 23: Napa Oxbow RiverStage, CA
Aug 25: Bend Hayden Homes Amphitheater, OR
Aug 27: Troutdale McMenamins Edgefield, OR
Aug 28: Redmond Marymoor Park, WA
Aug 30: Salt Lake City Sandy Amphitheater, UT
Sep 01: Morrison Red Rocks Amphitheatre, CO
Sep 03: Grand Prairie Texas Trust CU Theatre at Grand Prairie, TX
Sep 04: Austin Moody Amphitheater @ Waterloo Park, TX
Sep 06: Atlanta Cadence Bank Amphitheatre at Chastain Park, GA
Sep 07: Franklin FirstBank Amphitheater, TN
Sep 09: Boston Leader Bank Pavilion, MA
Sep 10: Mashantucket Premier Theater at Foxwoods Resort Casino, CT
Sep 12: New York Beacon Theatre, NY
Robert Plant and Saving Grace feat. Suzi Dian
Oct 25: Belfast Ulster Hall, Northern Ireland
Oct 27: CorkEveryman Theatre, Ireland
Oct 28: Galway Town Hall Theatre, Ireland
Oct 30: Sligo Knocknarea Arena, Ireland
Oct 31: Dublin 3Olympia Theatre, Ireland
Nov 05: Edinburgh The Queens Hall, Scotland
Nov 06: Glasgow King's Theatre, Scotland
Nov 08: Aberdeen Tivoli Theatre, Scotland
Nov 09: Perth Concert Hall, Scotland