Cheeky chat show, radio and Eurovision host Graham Norton’s first boyfriend was a floppy-haired boy from Melbourne named Ashley.

Falling for the Australian while living in London, 55-year-old Norton’s home since the 1980s, Ashley’s sense of humour coaxed the then 20-something Irishman to let go of his hang-ups and have a little fun.

Not that Norton immediately recalls Ashley when reminded of that detail from his 2014 memoir The Life and Loves of a He Devil.

“I remember now,” he chuckles at his own forgetfulness while speaking over the phone as he waited for a train on a bustling Monday morning in the British capital.

“We spent a very long winter during our summer, living in his parents’ garage.

“Happy days!”

The overbearing morality of the Catholic Church in rural County Cork in the ‘70s prolonged Norton’s stay in the closet, with his Protestant upbringing meaning he was doubly an outsider.

He barely recognises the country now, in a good way, post-marriage equality and winning abortion rights. “It’s like Sweden!”

His second novel A Keeper, which follows the critical and popular success of his London Times bestseller Holding (2016), is a dual-narrative page-turner that draws on the bad old days.

Protagonist Elizabeth Keane returns to Ireland from contemporary New York after the death of her estranged mother and uncovers a secret stash of letters that change everything. Without spoiling too much, let’s just say the sections set in the ‘70s take a pretty wild turn.

“It’s a bit dark, isn’t it, a bit gothic, but hopefully not too brutal?” Norton asks.

Reassured that his latest book is wicked fun, he notes that dispensing with mobile phones and social media meant he could more easily spin a mysterious disappearance.

“Now we’re all available all the time, but it used to be you wouldn’t see people for weeks,” he says. “You just assumed they were getting on with their lives, but now you’d be calling the police.”

Hosting a cavalcade of oft-raucous celebrities on his hugely YouTubed The Graham Norton Show, Norton credits his A-list guests’ more unguarded moments to the fact they share their time together on the sofa. “If they’re on the couch with their peers, they’re more genuinely themselves,” he says.

Ever-unpredictable Harry Potter and Rake star Miriam Margolyes is the best combination with absolutely anybody, Norton reckons. And while he was star-struck by both Madonna and Cher, the guest who left the biggest mark on him was larger-than-life country music star Dolly Parton.

The pair memorably shot the Graham Goes to Dollywood special together in Tennessee in the shocking aftermath of 9/11. Despite the fraught circumstances, he says she was a genuine delight to be around. “That was the most meaningful experience, because I got to spend so much time with her.”

Few guests become friends, but late Star Wars hero and author Carrie Fisher, who shared his mischievous sense of humour, was an exception. He even took her as his plus-one to the eye-raising wedding of Liza Minnelli and David Guest, where Michael Jackson was best man.

“Carrie and I actually met as guests on Ruby Wax’s chat show, and I think, in a way, that’s how we bonded, because as host you’re really just a conversation butler,” Norton offers.

What does he make of Australia competing in Eurovision?

“I’m not against it,” he says, his voice raising an unconvinced octave, “the more the merrier, but I can’t pretend to understand it. But that’s one of the good things about Eurovision. Nobody understands it. It’s really, really crazy.”

Graham Norton’s The Keeper is out now, published by Hodder & Stoughton