"Did you know I can run 100 metres in 19 seconds?"
Rod Stewart, Sir Rod Stewart, is boasting about his physical prowess. And why not?
At the age of 80, hes still cavorting around the world, playing sold out shows, recording new music and even writing a book about his beloved model train set.
This weekend, hell play the coveted "legends" slot on Glastonburys Pyramid stage... although the former headliner isnt 100% happy about his billing.
"I just wish they wouldnt call it the tea time slot," he complains.
"That sounds like pipe and slippers, doesnt it?"
Hes also persuaded organisers to extend his set, securing an hour-and-a-half slot after initially being offered 75 minutes.
"Usually I do well over two hours so theres still a load of songs we wont be able to do," he says.
"But weve been working at it. Im not gonna make any announcements between songs. Ill do one number, shout next, and go straight into the next one.
"Im going to get in as many songs I can."
Its not like hes short of choice. Sir Rod has one of the all-time classic songbooks, from early hits with the Faces such as Stay With Me and Ooh La La, to his solo breakthrough with Maggie May, the slick pop of Do Ya Think Im Sexy? and his reinvention as a crooner on songs like Downtown Train and Have I Told You Lately.
The last time he played Glastonbury, in 2002, he was viewed as an interloper – sitting awkwardly on the bill beside the likes of The White Stripes, Coldplay and Orbital.
At first, "the crowd was wary" of the musician, who "looked to be taking himself too seriously", said the BBCs Ian Youngs in a review of the show.
But a peerless setlist of singalongs won them over. By the end of the night, 100,000 people were swaying in time to Sailing as if they were genuinely adrift on the surging tides of the Atlantic.
Amazingly, Rod has no memory of it.
"I dont remember a thing," he confesses. "I do so many concerts, they all blend into one."
One particular show does stand out, though. On New Years Eve 1994, Sir Rod played a free gig on Brazils Copacabana Beach, drawing a crowd of more than three million people.
But it wasnt the record-breaking audience that made it memorable.
"I was violently sick about an hour before I was supposed to go on," he confesses.
"Id eaten something terrible, and I was in a toilet going, huerrrgurkurkbleaggggh
"I didnt think I was going to make it but luckily they got a doctor to sort me out."
Were talking to the star about a month before Glastonbury at the Devonshire, a relaxed, old-school boozer just off Piccadilly Circus thats become the favoured haunt of everyone from Ed Sheeran to U2.
Its a bit too early for a drink, though, so Sir Rod orders up a venti coffee, shooing away an over-eager assistant who attempts to stir in his sugar.
Hes dressed in a cream jacket and black jeans, which sit above the ankle to show off his box-fresh, zebra-striped trainers. His white shirt is unbuttoned far enough to display a diamond-encrusted necklace with the crest of his beloved football club, Celtic.
And then theres the hair. A bleached blonde vista of windswept spikes, so famous that it earned a whole chapter in the singers autobiography.
Steve Marriott of The Small Faces once claimed that Sir Rod achieved this gravity-defying barnet by rubbing mayonnaise into his scalp, then rubbing it with a towel.
This, says the musician, is utter "bollocks".
"Nah, nah, nah. I used to use sugared hot water, before the days of hair lacquer. And I couldnt afford hair lacquer, anyway."
But what really sets Sir Rod apart is that voice.
Raspy, soulful, raw and expressive, hes one of rock and rolls best interpretive singers. Theres a reason why his covers of Cat Stevens First Cut Is The Deepest or Crazy Horses I Dont Wanna Talk About It have eclipsed the originals.
So its a surprise to learn that he was discovered not for his vocals, but his harmonica skills.
That fateful night in 1964, hed been at a gig on Twickenhams Eel Pie Island, and was drunkenly playing the riff from Howlin Wolfs Smokestack Lightnin while he waited for the train home, when he was overheard by influential blues musician Long John Baldry.
"As he described it, he was walking along platform nine when he noticed this pile of rubble and clothes with a nose pointing out," Sir Rod recalls.
"And that was me playing harmonica."
At the time, he "wasnt so sure" about his singing voice. But, with Baldrys encouragement, he started to develop his signature sound.
"I wanted to always sound like Sam Cooke and Otis Redding, so thats the way I went," he says. "I suppose I was trying to be different from anybody else."
Sir Rod began his ascent to stardom with the Jeff Beck Group and the Faces, a boisterous blues-rock outfit heavily inspired by the Rolling Stones – both on and off the stage.
They were regularly so drunk hed forget the words to his own songs, he admits. In the US, the group received a 40-year ban from the Holiday Inn hotel chain after racking up a $11,000 bill (£8,000 – or £54,000 in 2025 money) for trashing their rooms.
"We only did it because the Holiday Inns would treat us so badly, like we were the scum of the earth," he says.
"So wed get our own back by smashing the hotels up. One time we actually got a couple of spoons and chiselled through the walls to one anothers rooms.
"But we used to book in as Fleetwood Mac, so theyd get the blame."
How come he never succumbed to drink and drugs, like many of his contemporaries?
"I never was a really druggy person, because I played football all the time and I had to be match fit," he says.
"I would use the word dabble. Ive dabbled in drugs, but not anymore."
Perhaps a more destructive force was the singers womanising.
He wrote Youre In My Heart for Bond girl Britt Ekland, but they split two years later, due to his persistent unfaithfulness.
His marriage to Alana Stewart and relationship with model Kelly Emberg ended the same way.
"When it came to beautiful women, I was a tireless seeker of experiences," he wrote in his memoir.
"I didnt know how to resist. And also... I thought I could get away with it."
He thought hed settled down after marrying model Rachel Hunter in 1990, but she left him nine years later, saying she felt she had "lost her identity" in the relationship.
The split hit Sir Rod hard.
"I felt cold all the time," he said. "I took to lying on the sofa in the day, with a blanket over me and holding a hot water bottle against my chest.
"I knew then why they call it heartbroken: You can feel it in your heart. I was distracted, almost to the point of madness."
However, since 2007, the star has been happily married to TV presenter / police constable Penny Lancaster, with the couple reportedly renewing their vows in 2023.
Last week, they celebrated their 18th wedding anniversary with a trip on the Orient Express from Paris, where they met in 2005, to La Cervara in Portofino, where they held their wedding ceremony, in a medieval monastery.
These days, Sir Rod says, family is his priority.
"Ive got eight kids all together, so sometimes Ill wake up in the morning and see all these messages, Stewart, Stewart, Stewart, Stewart… and its all the kids. Its just gorgeous."
His youngest, Aiden, is now 14, and becoming an historian of his dads work.
"Hes gone back and listened to everything Ive done, bless him," says the star. "He knows songs that I dont even remember recording!"
His Glastonbury appearance coincides with the release of a new greatest hits album – his 20th. ("Is it really?" gasps Sir Rod. "Oh gawwwwd.")
So how does it feel to look back over those five decades of music?
"Oh, its tremendous," he says. "Its a feeling that youve done what you set out to do.
"I dont consider myself a particularly good songwriter," he adds. "I struggle with it. It takes me ages to write a set of lyrics.
"So I dont think Im a natural songwriter. Im just a storyteller, thats all. A humble storyteller."
Maybe – but this humble storyteller is going to draw a crowd of thousands when he plays the Pyramid Stage on Sunday afternoon.
"You know, its wonderful," he concedes. "Ill be in good voice. Ill enjoy myself. I dont care anymore what the critics think.
"Im there to entertain my people."