berdeen schoolboy Angus Forfar will never forget his 14th birthday. He makes his operatic debut next Friday and is celebrating his birthday surrounded by glamorous, young female opera singers.

Today’s rehearsal breaks for everyone to sing him “Happy Birthday” and eat Pavarotti-sized portions of chocolate cake. They toast him with sparkling water and then it is back to work on Benjamin Britten’s opera inspired by the chilling Henry James ghost story The Turn of the Screw.

Angus sings the treble role of 12-year-old Miles, one of the main characters in this production, as part of Aberdeen International Youth Festival. The other parts are played by young, professional singers chosen by artistic director Gidon Saks, who heard them perform during his international travels as an operatic bass-baritone and teacher at Ghent Conservatoire in Belgium.

Rehearsals at the Lemon Tree Studio are held seven days a week. But Angus is getting a half-day off today for his birthday and has plans for a film and food with friends and family later.

It is a warm, sunny day outside the darkened theatre and seagulls are competing with the soaring sopranos for vocal centre stage.

Performing with Angus is Katrien Nauwelaerts, 22, a student at the conservatoire of Antwerp, who is playing Miles’s little sister, Flora. As they walk together across the stage, singing, Saks tells them to think of poo when they sing a particular phrase, so they can capture the mood of contempt he is looking for. It seems to work.

Angus, a pupil at Robert Gordon’s College, moved to Aberdeen from England a year ago. “I used to sing in Chelmsford cathedral choir and now sing in St Andrew’s cathedral choir here in Aberdeen.

“Opera is different because it’s not just singing; you have to get your cues right and come on and off at the right time. It is hard work and it’s quite tiring,” he says during the cake break.

His family’s musical credentials are impressive. “Dad played the guitar in a punk rock band when he was in Japan teaching Japanese students,” says Angus, pleased at the kudos of a punk rocker dad.

Over the next weeks 700 performers from all over the globe will gather in Aberdeen for the 34th festival of youth arts, a 10-day carnival of music, theatre and dance with 90 performances in the city and across the north east. The festival was launched in 1973 as an international event for youth orchestras and has grown to embrace a broad range of the arts. The children of some of the original performers are now taking part.

The festival press officer, Annie Woolridge, says: “There is something magical that happens here. People form friendships that endure. Some people have come here as performers and then returned to spend the rest of their lives in the north east or elsewhere in Scotland. There have even been marriages between festival performers.

“When you bring so many people together with a shared passion for music and theatre, it’s bound to be a memorable experience for everyone.”

Opera is a relative newcomer to the festival. This is the seventh operatic production to be staged. “It was only supposed to be a one-off,” says Saks.

“We were only supposed to do it for one year. But it was such a great experience for all of us and we got such a great response from the audience that Shell decided to renew the sponsorship, which they have thankfully renewed every year and secured us,” he says.

The opera singers come from the Netherlands, the United States, Germany, Belgium and London. The conductor and repetiteur are from Sweden and his assistant is from Paris.

“I came to Aberdeen earlier this year and listened to some local children, and I thought Angus had the potential to do the role. He seemed excited by the prospect. I don’t think he’s ever sung an operatic role, so this is a big challenge for him,” says Saks.

He is the founder of this Opera Garden project, named after the famous Aberdeen opera singer Mary Garden, who founded the Lyric Opera of Chicago, one of the world’s leading opera companies.

Saks rates the festival engagement highly. “It’s a hugely satisfying and wonderfully creative process and, I have to say, it gives me the most pleasure of anything I do over a year.”

This year’s production, with the audience and 13-strong orchestra in the round, will incorporate filmed sequences assembled by three young local film-makers.

Less than a mile away, at the University of Aberdeen’s King’s College, are the temporary base for the Aberdeen International Youth Festival. The chief executive and artistic director, Stephen Stenning, is on the hunt for harps for an orchestral group and airline tickets for 16 dancers from the leading traditional dance school in Sri Lanka, whose funding to travel here has evaporated. The boyish-looking former actor appears to relish what must sometimes feel like riding a roller coaster.

The Sankanjalee dance troupe comes from an area that was hit by the tsunami. “Sadly, we have hit a last-minute problem with the funding they thought they were going to get for their tickets. So, we’ve three days to raise Pounds 10,000 and get them over here. If they come, they will be great,” says Stenning with enviable calm.

With groups travelling to Scotland from 16 countries, including China, Ghana, the Philippines, Azerbaijan, the United States, Israel and Hungary, it is not surprising that last-minute hitches happen with visas and travel arrangements. Fortunately, the festival staff of 10 will swell to 70 once the programme gets underway.

One highlight this year will be the first performance of the newly formed Grampian Youth Orchestra, made up by musicians from Aberdeen, Aberdeenshire and Moray making the interim step from school orchestras to the National Youth Orchestra of Scotland, which this year performs the festival’s opening concert at the Music Hall on Wednesday next week.

Julian Clayton will conduct the inaugural performance by Grampian Youth Orchestra in a programme of works by Bach, Barber, Mozart and Voskanyen on August 7 at Queen’s Cross church. For the first time, there is a nine-day residential element for the orchestra to create a concert for the performance, says Stenning.

Another first this year will be performances by the best local bands from Aberdeenshire’s Youth Music Initiative, bringing a more contemporary musical feel to the festival programme at the Tunnels city centre venue on August 10.

And the National Youth Jazz Orchestra of Scotland will perform big band standards by Count Basie and Duke Ellington on Thursday next week at the Beach Ballroom.

Homegrown drama talent also gets the chance to flourish, with a new festival commissioned play, Finding Aberdeen. It is supported by the National Theatre of Scotland in conjunction with local professional company Abderite Theatre, performing at the Lemon Tree Studio on August 7.

The festival dance gala on August 10 at His Majesty’s Theatre will showcase three new pieces, choreographed and performed by students at the festival’s dance summer school. The evening will also feature highlights from international young ballet and contemporary dancers from Norway, Israel, the Hungarian Dance Academy, a Ukrainian dance ensemble from Canada and Sankanjalee (providing they get funding for their airline tickets).

Stenning recalls an impromptu jamming session one year between Algerian traditional musicians and classical European orchestral players. “We have to schedule time for that as well,” he says, “the things that happen informally.”

The highlights of this event for the performers may be unseen by the public. Spontaneous collaborations in halls of residence seem to be the life-blood of this cultural extravaganza, good times to remember years after the cello cases and dance shoes have been packed up for the journey home.

Aberdeen International Youth Festival, August 2-12; www.aiyf.orgbooking, www.abdnboxoffice.comwww.lemontree.org