Charlotte Church's voice is the stuff of dreams. Appropriately, she is singing for a charity that specialises in making fantasies and wishes come true.

The Make-a-Wish foundation helps children with life-threatening diseases and a ball held at Blenheim Palace will raise money to help fulfil their hopes. The angelic soprano - who welcomed the Millennium at the Dome - will be a guest at the event on May 20.

Jayne Watson, the Oxfordshire organiser, says the ball is growing in size and splendour. Formerly held in the Orangery, it has expanded into the palace state rooms. She says: "Our other special guest, besides Charlotte Church, is Roxanne Pinfold. The six-year-old from Headington has leukaemia and recently went on a wish to Disneyland. Roxanne says she's looking forward to being a princess for the evening."

The brave girl and her parents will be picked up in a limousine, then ferried out to Woodstock for the champagne reception. She will present Charlotte with a bouquet.

"Roxanne will be the only child attending, as evening events are often too much for most Make-a-wish children. They usually attend an event at Silverstone later in the year."

The ball - now in its second year - will still be well-attended by grown-up patrons, however. In 1999, 130 people attended, but Jayne expects a crowd of 300 this time around.

Champagne, dinner and dancing are the backbone of the evening, but the ball will also feature an auction and raffle. "We will be offering some Beatles photographs, gorgeous old images of the Fab Four in the 60s," Jayne explains. "Gary Lineker will provide a day's golfing in his company. We also have a holiday at a villa in Florida and a house in Scotland." Money raised will help Make-a-wish children, including five in Oxfordshire. Past requests have included computers, Playstations, meeting Michael Schumacher and Paul Nicholls.

"A young lad called Sam asked for a room make-over. We gave him the option of a designer or all of us. In the end, we worked together and all became great friends," she recalls. "We knew nothing about decorating, but over time we managed to make it beautiful. He was really pleased.

"Another boy, Daniel, wanted to see Dr Doolittle and got to meet Julie Andrews. Chris had a computer wish we managed to fulfil, while Brett had an off-road bike.

"We do have a lot of Disneys. It's the epitome of childhood, plus, some of it's escapism. Disney is portrayed as a magical place. When families are going through trials and tribulations, it's nice to focus on something away from hospitals and illness." Jayne became involved in Make-a-wish after losing her own son in a motorbike accident four years ago. Charity work helped fill the gap James left.

Her own bereavement makes it easier to cope with the fact that some of her clients will die. "These things happen. But I learned from James's death that you have to look at the positive side or else you sink.

"What we are doing is taking the child away from the misery and pain, taking their minds off it and giving them something special to remember."

Tickets are still available. Please ring 01865 300121 for further details.