Singing for his supper wasn’t something Tim Jones was expecting on a recent trip to America, but thanks to the ash cloud that’s exactly what he ended up doing.

But as a singer in one of the world’s best a capella bands Out Of The Blue, with numbers like Lady Gaga’s Poker Face under his belt, it wasn’t a hardship for the Oxford student.

And as he was on tour at the time the group just had to rely on the goodwill of the Yanks to house and feed them between gigs.

“We went on tour for two weeks and stayed for three,” Tim laughs.”But we were lucky, we had some very generous hosts on the West Coast, although some of us missed our exams so it was quite stressful.”

Although Out Of The Blue won the Voice Festival UK last year and came runner-up in the US, you may not have come across them.

But if you’ve been in Oxford’s Cornmarket this week you’ll know exactly who I’m talking about and will have already bought tickets to their one-off annual charity concert at the New Theatre on Monday. Because not only are they sensational, but all the profits go to Oxford’s Helen and Douglas House.

So who are Out Of The Blue then?

“OOTB, Oxford’s only all male vocal sensation, has been in existence for 10 years now, and its 13 members recycle themselves as people arrive at and leave Oxford,” Tim tells me.

A capella means singing without musical accompaniment, so what Out Of The Blue lacks in orchestral support it more than makes up for in imitation covering a dazzling variety of genres.

“There’s something very unique about our performance in the a capella world,” Tim says. “We imitate instruments as well with emphasis on each individual’s strengths. You are allowed your own personality and character on stage and I think that shines through. Put it this way, there’s lots of humour involved because although we’re professional we don’t want to do anything too serious. So it’s still fun and exciting but we rarely stand still, and the focus isn’t purely on the music alone.”

The ensemble still puts the hours in though to get their performance as perfect as possible, with six hours a week of rehearsals to fit into their busy lives.

“At the moment we’re rehearsing more because of the New Theatre performance, so we’re busking in Cornmarket every day as well to promote the concert on Monday,” Tim says. “After that Out Of The Blue will be off to the Edinburgh Fringe to a capacity crowd. We’ve sold out there for the past three years.

“But the New Theatre gig is still the big one,” Tim agrees. “It’s the culmination of everything we’ve been working on this year and a whole new repertoire of songs. But it’s such a fantastic venue and it’s a massive performance for us.”

As far as Tim goes this is the end of the Out Of The Blue road for him. With his finals coming up, he’s going to pass his a capella hat on to a deserving fresher, making Monday’s performance all the more poignant. “It’s something you really have to consider when you join – how much you are capable of giving, but the word is getting out about Out Of The Blue and more and more people know about us. So although it’s a big commitment the enjoyment capacity is huge.”

* Out Of The Blue are at Oxford's New Theatre on Monday. Call the box office on 0844 8471585.