He is the biggest-selling classical musician on Earth. His 40 million sales even outstrip global phenomenon Beyoncé and he has played to more than 15 million fans worldwide, fronting the largest privately owned orchestra on the planet.

But now the universally acclaimed Dutch conductor and violinist André Rieu, who owns a rare Stradivarius violin and lives in a castle previously owned by a French musketeer, is truly shooting for the stars.

He wants to perform on the Moon.

The universally acclaimed Dutch conductor and violinist André Rieu is truly shooting for the stars. He wants to perform on the Moon

The Dutchman is deadly serious and has been in touch with billionaire space cadet Richard Branson about playing his lunar tune. ‘I’m thinking big and Richard’s thinking big too,’ Rieu reveals. ‘We made contact and he promised me that he was going to build a hotel on the Moon and I promised him that I’d be the first to play there. But he’s taking his time! I’m ready to go. I would like to get up there and play The Blue Danube waltz.’

Rieu turned 70 this year but looks as lithe and healthy as Branson, a year his junior. ‘I stopped drinking alcohol 18 months ago,’ he tells me. ‘I was in the middle of a glass of wine and I thought, “I’m not really enjoying this.” I was drinking wine every day. I put down the glass and haven’t drunk since.

‘And I feel great, on stage and in life. I have more energy, more clarity. I worry less too. Maybe it has made me a nicer person. But it was a shame because I’d just had six electric wine-coolers installed, full of beautiful wines.’

For the first time in his professional life, Rieu, estimated to be worth £31 million, admits that he is finally able to relax financially. His Johann Strauss Orchestra plays about 100 shows a year and costs ‘approximately £1 million a month whether we are on the road or not’, with 120 people on the payroll, plus the same number of freelance employees.

Business is booming. Rieu’s repertoire of popular classics is one of the world’s biggest live draws and he remains among the highest-grossing touring artists, alongside the likes of The Rolling Stones and Bruce Springsteen. ‘And like Springsteen, I am the boss,’ says Rieu. ‘Although Bruce is, of course, ‘The Boss’, we actually run very similar organisations: we’re extremely good to our people and their families.’

Yet on the road, Rieu maintains a ‘no sex, drugs and rock ’n’ roll’ rule. ‘Although the sex part, who knows? I’m not that nosey!’

Rieu’s wife of 44 years, Marjorie, mostly stays at home, overseeing the smooth running of his shows from their medieval castle in Maastricht.

In recent years, Rieu has become more of an orchestral showman than a solo violinist, but he still wields a 1667 Stradivarius, previously the property of English nobility, in concert. The impossibly valuable fiddle travels with its own bodyguard.

His latest ‘Strad’ was purchased (‘for many millions of euro’) in Vienna. ‘There are only 400 in the world but I don’t feel like I own the violin. Although I bought it, I’m the caretaker. But I play it every day,’ he adds.

Rieu’s new album, Happy Days, is a welcome shot of good cheer in the uncertain current climate although, as an international artist, he is reluctant to get drawn into political debate. But, referring to the UK’s upcoming General Election, he notes that ‘being an orchestra leader is a little like being a prime minister, and a good prime minister should be there for the country, not the other way around – you must keep your people happy.’

Personal happiness for Rieu is hanging out with his young grandchildren or tending his orangery, to which he has recently introduced two exotic Ethiopian birds.

For the first time in his professional life, Rieu, estimated to be worth £31 million, admits that he is finally able to relax financially

Life, the King of the Waltz sighs, is quick-stepping by. In his heart, Rieu confides, he still feels 17. ‘Although I intend to live to 140,’ he deadpans. ‘So, I’m halfway there already and there is still a lot to achieve.

‘I used to say “the sky is the limit”, but we have progressed so now it’s the Moon. I will go there and perform, I promise you.’

Of course, there’s only one problem with playing gigs on the Moon – no atmosphere.

‘That’s a good one,’ Rieu hoots at the time-honoured gag. ‘Let me get a notebook and write that down. Hopefully, while I’m doing that, Branson will start building his hotel.’ He impatiently brandishes an imaginary baton. ‘Get on with it, Richard!’