"I was a shell of the person known as Martin Kemp. I had to learn how to be me again."
How to convey the life-changing significance of Spandau Ballet for an awkward 14-year-old feeling misunderstood? Martin Kemp is smiling and nodding. He's heard it all before.
But not from me. I tell him where I was the first time I heard To Cut a Long Story Short, way back in 1980.
"I was kneeling on that horrid brown carpet in the dining room, holding a microphone up to a transistor radio," I say. "Spandau Ballet came on and the world shifted and in that moment I understood who I was and where I belonged."
Kemp, patiently waiting to get a word in edgeways, has got better looking with age; at 56, he's a silver fox gone Arctic with a head of white hair, his eyes blue as ice chips.
He's also been going to the gym almost every day in preparation for a stint in Chicago on the West End, taking over from Cuba Gooding jnr.
That's what we're supposed to be talking about. But I'm busy telling him I used to save my dinner money and live off cooking apples so I could afford a cassette of Spandau's album.
"I know that feeling," he says. "It was the same for me with T Rex. Maybe not the cooking apples - but music was expensive, so when you scraped together enough for an album, you played it over and over.
"Music was far more tribal in the eighties; you were into one band and that was it. Kids nowadays have access to many more genres, so they look beyond their pop tribe and that's a wonderful thing."
I'm still entirely tribal, but Kemp is a glass-half-full kinda guy. He also knows what he's talking about: his 25-year-old son Roman is a breakfast show star on London's Capital FM.
"I honestly don't think pop has been in better shape since I was in the charts - Ed Sheeran is a genius."
I find it hard to write the next line. I always loved Tony Hadley best, but I daren't spill the beans to Kemp because there was a big fallout and now Spandau Ballet has a new singer, Ross William Wild, who is 30.
Kemp says he's fabulous. But I am unconvinced. It's like my parents have split up, and my mum is trying to introduce me to her new boyfriend.
"No!" cries Kemp. "Don't say that! He's amazing; we played a gig to 600 people in Notting Hill; it was one of the best moments of my life."
Poor Dad. I mean, poor Tony. Although he was the one who left last year, announcing it on Twitter. "But your brother Gary wrote the Spandau songs," I say to Kemp. "Will Tony be allowed to play them any more?"
"I can't answer that," he says, which means he won't. The band first went their separate ways in the early nineties, before reforming in 2009. Meanwhile, the Kemp boys appeared as Ronnie and Reggie in The Krays. More roles followed in the US - until Kemp started to prowl about Walford.
"Ladies of a certain age remember me from Spandau," he says. "Then there's a new lot that knows me from EastEnders. There's something nice about crossing generations like that."
Kemp is softly spoken with a gentle manner; despite his air of repressed menace down the Queen Vic, he's never thrown a punch in his life.
"I'm a shy person," he admits. "As a child I was painfully embarrassed by everything. When I lack confidence now, I channel a bit of [EastEnders character] Steve Owen and that transforms me."
It was thanks to his mother that Kemp had the courage to get on stage at all. She sent her sons to a drama club in Islington for 10p a lesson. They amassed impressive small-screen CVs; cast in everything from Jackanory to Dixon of Dock Green.
"I would recommend it for all kids," he says. "You learn how to channel your charisma. Those classes changed the lives of kids like me."
They lived in a run-down town house and his parents had very little money. It's a source of quiet pride that the boys were able to buy their parents a house when they hit the big time. Family means a lot to them.
Kemp has been married for 30 years to Shirlie Holliman, the blonde one from Pepsi & Shirlie, backing singers to Wham! Kemp saw his future wife on Top of the Pops and was smitten; even the fact she brought George Michael along on their first date did not deter him. The singer's death, in 2016, hit Kemp hard.
"For us, it wasn't just George Michael who died. He was family."
It isn't the only trauma Kemp has faced. Before appearing on EastEnders, in 1998, he had been recovering from brain surgery for four years. Mercifully his two tumours were benign and a protective metal plate was inserted into his skull - but the side effects, including epilepsy, were devastating.
"I was a shell of the person known as Martin Kemp. Clinically depressed and unable to function properly. I had to learn how to be me again. When the call came from the BBC, I had no idea if I could even learn the lines. But it gave me something to push towards and I will always be grateful."
Kemp won no fewer than nine awards during his four years on the soap, but is unlikely to return as his character was last seen in a burning fireball after a car crash.
"I've turned my hand to a lot of things, but I'm not sure even I could escape from the car and scramble to safety in 10 seconds."
Since then he's been a judge on Let It Shine and braved Celebrity Big Brother. But his three-month stint as Billy Flynn will be rather more front of house. "I was asked to do Chicago 10 years ago, but the timing just didn't work out. So it feels like unfinished business. It will be the first time I'll be singing alone on stage."
After his run, he tells me that the band will be doing a few gigs. I'm excited - I've never seen Spandau Ballet live. Then a terrible thought occurs. Those words every audience dreads: "Here's one from the new album." You wouldn't do that to us, would you, Martin?
"Absolutely not! I love that moment, when we play the opening of True or Gold and watch a huge smile break out on everyone's faces."