Michael Ball would be the first to admit that life on the road with his singing partner Alfie Boe is hardly rock‘n’roll.

They do not attempt to emulate the behaviour of rock stars of the past, who after a gig would go out on the razz all night before returning to the hotel to throw a television set out of the window. In fact, Ball and Boe use their television sets in a rather more sedate manner, as we shall see.

The singing duo have learnt to help each other manage the highs and lows of performing in an eminently reasonable way. Ball takes up the story. “It helps to have each other there. On and off stage, the only person who knows what you’re feeling is the other performer. You both understand the comedown at the end of a performance and you have to normalise it.

“I fully understand why some artists go mad. They come off stage and say, ‘I need to continue that buzz’. But you ain’t going to find it anywhere else. You can’t reproduce it chemically. You just have to wait for the next gig. You might as well settle down with a box set!”

A defiantly uncool, unthreatening approach is one of the many reasons why Ball and Alfie Boe have become so popular as a duo

Which is exactly what the decidedly un-rock‘n’roll Ball and Boe do after a gig. Ball reveals “neither of us is drinking at the moment. After a show, we will enjoy that exciting moment and have a bit of food with the musicians. Then we’ll put the telly on!” In case you’re wondering, Ball’s current box set of choice is Mindhunter, the acclaimed Netflix period drama about criminal psychology.

Ball, 55, who possesses a very likeable, self-deprecating sense of humour, says that it has never been his aim to be the height of fashion. “I don’t think you last very well in this business if you’re trendy because trends come and go. I’m now in my 34th year as a performer, and I’ll never go out of fashion because I was never in fashion!”

This defiantly uncool, unthreatening approach is one of the many reasons why Ball and Boe have become so popular as a duo. In addition to the beautiful harmonies they conjure up covering classic songs, the pair’s self-effacing, decidedly un-starry attitude to their work has struck a chord with audiences.

Ball says that this down-to-earth outlook and refusal to take themselves too seriously forms the basis of his relationship with Boe. “Alfie and I have a very British thing – we enjoy taking the mick out of each other and pulling the rug from underneath each other.

The duo recently released a second album ‘Together Again’ which went to went straight to number one

“We’re great mates and have huge respect for each other’s talents and achievements, but we also really like winding each other up. It’s a very British kind of friendship.”

The singer, who has twice won the Olivier Award for Best Actor in a Musical – in 2008 for Edna Turnblad in Hairspray and for Sweeney Todd in 2013 – continues: “'You often take the mick out of the people you like best. We like that sort of self-deprecation. I’d rather take the mick out of myself before anyone else does. I know they’ll do it, so I’d rather get in there first!”

Ball and Boe, who have become close friends since meeting on a production of Kismet at the London Coliseum 11 years ago, have turned into the surprise recording and performing hits of the last year.

Their first joint album, Together, went platinum in just six weeks last year and proceeded to sell an eye-watering 640,000 copies. The follow-up, entitled, ahem, Together Again, went straight to number one last month, beating the much-ballyhooed new Stereophonics album by just 35 positions. It contains Ball and Boe’s takes on such standards as, “New York, New York”, “White Christmas” and “Bring Me Sunshine”.

Ball represented the United Kingdom in the Eurovision Song Contest, finishing second with the song ‘One Step Out of Time’ in 1992 (Rex)

Now the duo are in the midst of a major nationwide arena tour, which culminates in a show at the O2 in London this week. Ball smiles at the prospect of playing the O2, saying it is “bloody daft! But I get more buzz from live performing now than I have ever done. I’m totally un-cynical about what I do. I know you could go out there one day and no one would be there.

“But for the time being, I’m so happy to know that there will be moments where there is dead silence in the audience and the only thing they’re concentrating on is the emotion you’re imparting and the memories you’re creating. You can generate a phenomenal relationship with an audience. It’s very gratifying, a real privilege.”

The singer, who originated the role of Marius in the original London production of Les Miserables in 1985, carries on that, “a show is always about two parties – you and the audience. One doesn’t work without the other. It’s never just about you. That’s why live performance will never go away.

“This industry used to be about record sales, and some acts saw live performance as a necessary evil. But now if you can’t do it live, you won’t get very far. Look at Ed Sheeran, Adele or The Rolling Stones – they are all brilliant live.”

He won the Olivier Award for Best Actor in a Musical in 2008 for his role as Edna Turnblad in ‘Hairspray’ (Rex)

Ball, who also hosts a show on BBC Radio 2 every Sunday morning, considers why his partnership with Boe has chimed with audiences. “A lot of people love the music we do. They connect with it and are prepared to go out and find it.”

But, he adds, something else may lie behind their appeal, too. “When we unveiled what we were doing last year, it was a strange time in this country. Votes were not going the way people expected, and there was a lot of uncertainty and disparity. We represented unity and fun and a respite from all that.”

So, I suggest mischievously, might the headline to this piece be that Ball and Boe provide an antidote to the uncertainty caused by Brexit and President Trump? “That might be a bit dramatic!” laughs Ball. “People saw our TV special and concerts and recognised two blokes they knew and may have liked. The idea of us coming together with no agenda appealed to people.

“We were saying, ‘Look, this is what we do. It has no politics – it’s something very simple and uncomplicated. Please enjoy it. It demands nothing else of you’.”

Ball reflects on his tremendous chemistry with Boe. ‘There is a unique sound that only two voices can produce.’

Ball and Boe will be working on solo albums next year, but I put it to the singer that the clamour for them to reunite after that will be overwhelming. “Clamour?” deadpans Ball, adopting a faux-luvvie tone.

“If there is a clamour, then it would be churlish to deny people. I would have to say, ‘The nation simply insisted we got back together. Much as I would have loved to, I couldn’t refuse. It was my civic duty!’”

Before we part, Ball reflects on his tremendous chemistry with Boe. “There is a unique sound that only two voices can produce. When they mix, something special happens. I don’t know what the chemical formula is, but it happens to work. Why do two tastes go together? Why does duck and orange work as a combination or red wine and cheese?”

Ball bursts out laughing. “And yes, before you say it, I provide the cheese!”