Forget the National Concert Hall – if it’s posh venues you’re after look no further than the London Palladium.

From Louis Armstrong, Shirley Bassey and Miss Piggy to Tom Jones, Judy Garland and The Beatles, everyone who’s anyone in the world of showbiz has graced the revolving stage at the 125-year-old Grade II-listed theatre, often with kings and queens gazing down on them.

The rock royalty in attendance tonight is Elton John who’s celebrating the release of his new Who Believes In Angels? album with its co-creator Brandi Carlile and 2,300 of their closest friends and fans.

The celebrity count is high with Andrew Lloyd-Webber, Sasha Baron Cohen, Björn Ulvaeus, Sophie Ellis-Bextor, Jason Momoa, Sam Fender, Daphne Guinness, David Walliams, Matt Lucas, Ronnie Wood and, most impressively, Marty Whelan also wangling their way on to the guest-list.

Despite the recent infection which has caused sight loss in his left eye, the 79-year-old looks hale and hearty in his neon pink suit and lime green runners. Not to be outdone, his co-conspirator is sporting a diamante-flecked white number that turns her into a human mirror ball.

Although he’s performed here before, it’s Elton’s first time topping the Palladium bill.

“When I was a boy, I used to watch Sunday Night At The Palladium every week on TV and it was the most exciting programme, which you never failed to watch because they had big stars over from America,” he tells Brandi man and Elton mega-fan Dan Levy who’s conducting the public interview. “Bruce Forsyth hosted and they had The Beatles on it. It was incredible.

“I did a Royal Variety Performance here with Liberace. I thought, ‘Okay, Liberace, I’m going to get two fabulous costumes made.’ I had these coloured tailored suits hanging up in the dressing room we were sharing. And there was trunk after trunk of his. It was the night he wore the electric lightbulb suit, which lit up. I thought, ‘Fucking hell, you’ve won game, set and match!’”

Elton John and Brandi Carlile at the London Palladium. Photo: Ben Gibson.

While eager to get to the performing part of the night - you would be too if your band included Red Hot Chilli Peppers members past and present, Josh Klinghoffer and Chad Smith – Elton explains that the collaboration is born out of twenty years of close friendship and him wanting to help make Brandi as big a star here as she is in the States where she has eleven Grammy awards and two Emmys on her very long mantlepiece.

He takes responsibility for the Who Believes In Angels? recording sessions being fraught at first – see the Stories From The Edge Of Creation featurette on YouTube for a sample temper tantrum – and credits Carlisle with eventually turning them into one of the most rewarding experiences of his epic career.

“I wasn’t feeling very well. I was shattered after the tour, but I couldn’t walk away from the other people who were committed to this,” he says. “So my main thing was me stepping up to the mark. And once I got the song (‘The Rose Of Laura Nyro’) down that I really thought was great, I settled down. After four or five days in the studio, it was fantastic.”

Redolent of Goodbye Yellow Brick Road’s ‘Funeral For A Friend’/‘Loves Lies Bleeding’, the track in question pays tribute to Laura Nyro, the New York singer with a three-octave mezzo-soprano voice who Elton idolised.

“She was a huge influence on me in the early ‘70s,” he confirms. “Bernie Taupin and I used to listen to albums of hers like Eli And The Thirteenth Confession and the track ‘Eli’s Comin’’ which is referenced in our song. It was like she was inside me when I was writing the melody. On the day we recorded it, Brandi said, ‘You won’t believe it, it was Laura Nyro’s birthday today.’ So that made it even better.”

Sadly, another potential Grammy winner failed to make the cut.

“I wrote a song called ‘Your Bum Is Like A Magnet’ but it didn’t make it on to the album,” he rues.

For all of his benevolence towards the younger singer, the partnership is clearly a 50/50 one with both of their musical fingerprints on Who Believes In Angels?’s ten tracks.

After Dua Lipa, Sam Smith, Ed Sheeran and Chappell Roan pay video screen tribute to Elton, the talk turns to family.

“On my tombstone, I want nothing to do with Crocodile fucking Rock,” he jokes. “I just want it to say ‘He was a great dad.’”

Brandi later reveals one of her daughters to be the inspiration for ‘You Without Me’, a gorgeous ballad which is among Who Believes In Angels?’s gentler standouts.

“It’s when you realise you can no longer pick your child up,” she says before admitting that, “Motherhood took me by surprise, which is a big thing for a lesbian because it’s usually planned.”

Asked about the pushback against LGBTQI+ rights in Trump’s America, Elton notes that, “I’m a diplomat. I can’t speak about governments because then what’s going to happen to the AIDS money? What’s going to happen to PEPFAR (the US President’s Emergency Plan For AIDS Relief). I’ve got people’s lives at stake. I have an AIDS foundation that depends on money and I will go out there and fight for it as much as I can. But I can’t say, ‘You’re an asshole.’ You have to negotiate. You have to play the game. It’s tough out there but these things will pass.”

The perilous state of the world almost lead to Elton pulling the plug on Who Believes In Angels?

“I went round to Elton’s one morning when we were making … Angels and he was sitting there at the breakfast table with newspapers all over his plates,” Carlile recalls. “He was in an awful state and really upset by the goings-on. He said, ‘I just don’t think now is the time to make the album. If we’re not going to address this conflict (in Gaza) I can’t see us doing anything.’ I didn’t have a response right then but I walked away and wrote a song called ‘A Little Light’, the first verse of which is what I wish I’d said to Elton but, like most things, was easier to say in a song.”

“We recorded ‘A Little Light’, which is a such a joyous song, that day,” he nods. “You reminded me that as a musician, all I can do is put music out and try and bring people together.”

Elton John and Brandi Carlile at the London Palladium. Photo: Ben Gibson.

Leaving aside the impact it might have on the rest us, the new album has been a true “eureka!” moment for Elton.

“I have everything I’ve done behind me and it’s been amazing, but this is the start of my career Mark 2,” he proffers. “It’s given me a place where I know I can move forward. Who Believes In Angels? feels like going into another era and I’m pushing the door open to come into the future.”

Reflecting on Elton’s activism and how big a role model he was for her growing up in Ravensdale, WA, Brandi says: “I think you have to be so authentically, unapologetically you… and you can take those words of advice really seriously by looking at the entire career and life of Elton John. There’s never been anyone more eccentric, and more willing to stand out in the crowd, than this man right here.”
It turns out that Carlile used to be a teenage Elton John impersonator.

“My favourite Elton cosplay moment was when I was fourteen,” she laughs. “I had a white suit, gold shoes, yellow feathered sunglasses and I did ‘Honky Cat’. These were big transitional moments for me. It made my parents nervous, but also brought us closer together in that my family said, ‘We have to accept this freak!’”

There are gasps and laughter when Elton reveals that he’s the owner of 15,000 pairs of sunglasses – “We keep them in storage because I don’t have that big a house” – and then he gets his wish as Levy ends the interview and some very upmarket roadies clear away the throne-like seats they’ve been sitting on.

The word had been that Elton and Brandi would be performing a few intimate songs, but what follows is a full 90-minute gig, which is as heavy on Elton John classics (‘Tiny Dancer’, ‘Your Song’, ‘I Guess That’s Why They Call It The Blues’, ‘I’m Still Standing’ etc. etc.) as it is Who Believes In Angels? newbies (with its 100 mph boogie woogie piano, ‘Little Richard’s Bible’, is a match for any of the golden oldies).

There are also lovingly performed covers of ‘He’ll Have To Go’ and ‘Crazy’ which Carlile, a Patsy Cline devotee, absolutely nails.

There’s another mea culpa when Elton halts ‘Bennie & The Jets’ halfway through and apologises to the band for, in his excitement, playing it too fast.

It’s a wonderfully human moment in a night that genuinely gladdens the heart and confirms that, despite his retirement from touring, the sun definitely hasn’t gone down on Elton John yet.

• Elton John and Brandi Carlile’s Who Believes In Angels? is out now on EMI