I offer an apology straight away. "I'm old enough to want to call you Little Jimmy Osmond," I tell the former child star who had massive international fame with his brothers and as a solo artist.
Even down the transatlantic phone line, I can hear a benign smile forming on Jimmy Osmond's face.
"It was an amazing time. I thought every kid did what I did – I had my first hit record at five years old as a solo artist. In Japan and in Japanese. And then there was Long-Haired Lover from Liverpool..."
Indeed there was. Jimmy was nine in 1972 when he became the youngest artist to have a number one hit with this quirky little song.
He was the baby of the Osmond family, the ninth in a line-up which included Alan, Wayne, Merrill and Jay – who started performing as the Osmond Brothers in the 1970s – Donny and Marie.
The Osmonds racked up hit after hit including One Bad Apple, Crazy Horses, Love Me For A Reason and Donny's massive Puppy Love. Marie didn't miss out with hugely successful Paper Roses.
If you weren't there, it's hard to appreciate how popular the Osmonds were, particularly in the UK, and the fascination for their clean-cut image and an obsession with what their lives were like as Mormons.
Even Jimmy admits that there was a time, with Long Haired Lover, when he "wanted it dead".
"I didn't want to be remembered for that, but now I feel more grateful. It is what it is and everybody knows it. But it did open up an opportunity for me to be known as an individual. I would never have been in a show like Chicago, or had other opportunities, without it. But it's always made fun of. This Christmas someone called me to remind me it was the 40th anniversary – and I still hold the record as the youngest artist to have a number one."
So what does Jimmy remember of the Osmond experience?
"It was pretty loud!" he laughs. "You tell people your experiences and they won't believe you.
"There were a lot of artists at the time who were more talented, but there were just a handful of groups. Maybe us and the Jacksons. There was incredible success and adoration. You don't get that these days. It's spread pretty thin. In those days there were only two TV channels!
"The brothers have been performing for 54 years. A lot of families don't stick together in showbusiness, but our parents kept us grounded."
Even though Jimmy was "the baby" he developed a lot of the business side of the act and is president of Osmond Entertainment as well as running other businesses, including a spell in real estate. But, he says, he still relishes the chance to work with the brothers. Which brings us neatly to the show that will bring Jimmy and brothers Merrill and Jay back to the UK – Boogie Nights: The 70s Musical in Concert.
Boogie Nights was the West End's original jukebox musical, conceived by EastEnder Shane Richie and Jon Conway. Set in a provincial town at the height of the disco scene in the 1970s, it was the heartwarming story of loveable rogue Roddy O'Neil and the soundtrack was peppered with hits.
In its 2013 incarnation, narrative has been dispensed with so that it returns as a remixed concert version of the ultimate party show. There's live music, multimedia and non-stop hits. And when I say non-stop, I mean around 70 of the 70s' finest, including Disco Inferno, I Will Survive, Don't Go Breaking My Heart, Le Freak, You're My First, My Last, My Everything, YMCA, We Are Family, Boogie Wonderland and the Osmond hits Crazy Horses and Love Me For A Reason.
Jimmy – who appeared in Boogie Nights in 2004 – says he's delighted to be in the show again, and to be performing with his brothers.
"We're going to have a blast," he says. "It's something I know they're going to be thrilled to be a part of.
"The show does have elements of the play, but it's a bit more of a 70s celebration. The great thing about nostalgia is that there is a lot that people know and can participate in. And people do join in, people love to dress up.
"The timing is right for it. Things are a bit difficult for all of us. You can forget your troubles for two hours. It's wild and fun."
Jimmy married wife Michelle 21 years ago and they have four children aged between 18 and ten – Sophia, Zack, Arthur and Isabella.
He follows in the Osmond tradition by taking his family on tour with him.
"Last Christmas we did Jimmy Osmond's American Jukebox Show in a theme park. It was so much fun. The kids go to normal school, but they love to be on the road with their dad."
Would he encourage them to develop a showbusiness career?
"If they were talented enough. It's a different world today. What you need to have is a career that lasts."
Jimmy's career has certainly lasted, but he's considering "winding down" and concentrating on what he loves. "I want to back off from the serious stuff. It's boring. I had a mortgage company, but it just doesn't compare to showbusiness."
Boogie Nights: The 70s Musical in Concert is at Plymouth Pavilions on Wednesday, February 13. Box office: 0845 146 1460