Joseph Calleja and Michael Bolton met for the first time before their joint concert tomorrow at dinner at The Arches in Mellieha last night, but it's not like the two music giants need much by way of rehearsals.

If there were any doubts about the chemistry though, the two hit it off at the first embrace, enjoying a flowing conversation and exchanging heartfelt praise, despite grumbling stomachs and entourage, and a dinner anxious to be served.

"I think we're doing fine," they laugh after five minutes together and a question about on-stage chemistry. They later admit that they're actually mirroring each other.

And they're already talking about using this event as a platform for future collaborations.

It is a ping-pong of flattery between the two - "mutual admiration" - which should be translated into an explosive show when they join forces, literally, at Luxol tomorrow.

Bolton is on the coffee, having lapped up the sun all day aboard a boat, and Calleja, back home after a hard-earned break, following his successful six-show run of La Traviata at London's Royal Opera House, is in great form, displaying his trademark and attractive modesty, coupled with a sense of humour.

Once they establish whether Bolton had received Calleja's message that he couldn't make it to join him on the boat, and they go through a couple of other niceties, the two take their cues to express the honour of performing together.

It's hard to establish for whom tomorrow's concert is more important, but Calleja stresses on it.

"This is a mega star and we are very lucky to have him here," says the man who has had his fair share of success and is on a roll.

"Michael is not an opera singer, but he probably loves opera more than opera singers. He could have ignored this type of music and he would have been just fine. The greatest stars in his genre are those who show this kind of respect for opera. I find it flattering that those who sell millions of records, while we are happy if we sell 80,000, do this..."

"Excuse me, but you're booked until the next century," interrupts Bolton, repaying the compliment.

What Bolton does - embracing opera - has a beneficial ripple effect on the opera scene and singers, and is a vehicle to opening the genre up to a wider audience, Calleja explains.

They are in total accordance: the purist perception and overprotective approach to any genre of music can be damaging. Crossing over is not demeaning, or disrespectful to the art form. It allows artists to stand out and reach over, Bolton continues.

And Calleja is putting that thought into practice, singing Marigold with Winter Moods on the night.

"Being elitist is self-defeating for the art," he stresses. This attitude is just making opera smaller and smaller, leaving empty theatres.

"Opera is for everyone and tomorrow's concert is the way forward, he maintains.

"The Maltese have to understand that to have Michael twice in almost the space of a year is a great privilege and to have him in my concert is incredible."

They are about to start an impromptu rehearsal at table... But joking apart: "We're both professionals... When both parties know what they are doing, that's enough. Plus we have tomorrow and the day after and we hope the result will be brilliant."

In the case of his collaboration with Pavarotti, Bolton had met him the day of the show, so these two are actually ahead of the game!

Just hours before, Pavarotti had suggested a repertoire that Bolton was not familiar with. Over a phone call in a taxi, he hazarded his own suggestions... and after a pregnant pause, Pavoratti exclaimed: "Brilliant!" And Bolton started breathing again.

At least these two know what they're singing. "We've been looking at song lists, while touring the world. The repertoire includes some of the greatest songs and arias ever written," Bolton pre-empts.

He is a bit nervous about his Italian and will be producing his phonetic lyrics. He is also consoled by the fact that he is being relieved of some of the pressure with Calleja - "the real thing" - by his side.

When Bolton received an invitation to perform with the late Pavarotti it was a "tremendous honour"; he was terrified.

When he got an invitation from Calleja, following his concert last year, he saw it as an "embrace" from Malta - "not to be taken for granted". He may not have yet heard Calleja's voice at that point, but did so as soon as he knew the concert was going to happen.

Neither plans to steal the show on the night - if there is any competition between the two, it is restricted to humility and flattery.