Henley’s spectacular riverside jamboree — now 27 years old — has two heart-throbs in this year’s line-up. Stunning Welsh songstress Katherine Jenkins is sure to set male hearts a-fluttering, while West End star John Barrowman will undoubtedly have the ladies swooning on the manicured lawns in front of the Floating Stage.

But there is much more to Henley, which takes place between July 8 and 12, than interfering with the natural workings of the heart. There’s the usual rich variety of headline acts and support acts, from opera to jazz, from comedy to street theatre — and, of course, the traditional roving eccentrics without which Henley Festival wouldn’t be complete.

Festival director Stewart Collins believes that this year’s line-up is one of the strongest yet.

“It’s exactly the kind of wide-ranging package that we try to put together,” he says. “Having Katherine Jenkins is a fantastic way of raising the curtain on the festival, because she came to the festival a few years back, at the start of her career, and since then has gone from strength to strength. So it’s a great way for us to kick off.”

While Katherine Jenkins is wowing audiences on the Floating Stage, local singer-songwriter Rebecca Poole hopes to attract an enthusiastic home crowd in the Southern Electric Dome.

“I think it’s going to be one of the most frightening experiences I’ve had in my performing life,” she says. “There’s no worse critic than your best friend! But I’m also very excited about showing people I haven’t seen for a long time what I’ve been up to in London. So I hope lots of people I know will come and hear me sing.”

The opera theme continues on the Floating Stage on the second night, with Rebecca Evans, Gwyn Hughes Jones and George von Bergen in an evening of Puccini, presented by Radio 4’s James Naughtie, and featuring popular numbers from La Boheme, Tosca, Madame Butterfly and Turandot, among others.

“Puccini’s a personal passion, and I believe it’s one that a lot of people share,” says Stewart. “It’s going to be absolutely magnificent.”

John Barrowman makes his appearance on the Friday, in a night of music from the movies. Pure Gold from the Silver Screen is presented by another well-known name — the relatively local Sir Michael Parkinson — and also features rising West End star Kerry Ellis. The show is being recorded by BBC Radio 2 for broadcasting on Friday Night is Music Night in August, and, Stewart believes, will be “an extraordinarily strong, powerful and tuneful evening”.

A fun night is guaranteed on the Saturday night, as popular Broadway trio Three Mo’ Tenors take to the Floating Stage in their first UK appearance since performing at the Edinburgh Fringe Festival in 2006.

“We loved the Edinburgh audiences — they sang, clapped, even danced along during the show,” recalls counter-tenor Kenneth Alston.

“Much to our surprise, we received a standing ovation after every performance.

“People come to the show not really knowing what to expect. We do ten different styles of music — opera, Broadway, rock, jazz, blues, R&B, soul, spirituals, Gospel, and World music. There’s something for everyone’s musical taste and the audience really seems to appreciate that.

“When we were invited to perform at the Henley Festival we were delighted to accept. Not only is this the premier music festival in Europe but it’s minutes away from The Fat Duck — one of our producer’s favourite restaurants in the world!”

The final night, as always, is party night, and Stewart is delighted to have secured the Bootleg Beatles to lead the celebrations.

“Unfortunately the Beatles themselves are not available,” he jokes, “but the Bootleg Beatles are incredibly close to the real thing. It’s an absolute guaranteed formula for a fun evening.”

Other festival highlights include appearances by comedy stars Rich Hall, Arthur Smith and Jan Ravens, an evening of Flanders and Swann, and a special art exhibition celebrating the work of Salvador Dali to mark the 20th anniversary of his death.

Stewart is particularly proud of this year’s schools project, which has received official recognition from the London 2012 Inspire programme. Rings Around the World is a series of large murals celebrating the culture of the five continents, and will be on display throughout the festival.

“The festival itself is only five days but the organisation runs all year round, and most of the work in between times is with our schools,” Stewart says.

“So it’s very nice that that side of our work has been recognised by the London Olympics.”

The festival will end, as always, with a fireworks spectacular — and then, for Stewart, the hard work begins for 2010.

“The eternal problem for me always is following the previous year’s festival. Year after year I have to sit down and think, ‘right, got to do better’. But I’m very proud of this year’s programme. The five main concerts are all really different, so they should appeal to a really different audience.

“I think we’ve got a very strong and varied line-up.”

lFor full details and tickets, visit henley-festival.co.uk