With help from actors Emma Thompson and Stephen Fry, the teenage princes are tonight staging a comedy play, followed by a dinner-dance, for the Prince of Wales.

Mrs Camilla Parker Bowles, their father's long-time love, will be among the 100 guests at the special "royal performance".

Contrary to reports, the Queen is not attending the play as she is spending the weekend with her mother at Sandringham, her Norfolk estate, ahead of the Queen Mother's 98th birthday on Tuesday.

The show, staged at the new Orange Room conference centre in the grounds of Highgrove, the Prince's Gloucestershire home, near Tetbury, was to have been a surprise, until details were published in a Sunday newspaper.

William, 16, and 13-year-old Harry are acting in the hour-long Blackadder-style spoof devised by them as a gift for a "man who has everything".

The Highgrove party was organised, with the help of former royal nanny Tiggy Legge-Bourke, during the young princes' school holidays, well ahead of their father's birthday on November 14.

The Prince of Wales's spokeswoman Sandy Henney said: "We are not confirming any details of this private party given by Prince William and Prince Harry for their father."

"There are no media facilities and members of the media are not welcome at the venue."

Charles will celebrate his 50th birthday, on November 14, with a private family party.

On November 12, he will attend a gala dinner at Hampton Court, marking the "Travels with the Prince" exhibition of his paintings and those of artists travelling with him on overseas tours.

Also on November 12, the Prince will attend a Young Artists' Award lunch at St James's Palace.

Fifty entries will be displayed at the Hampton Court exhibition.

It is business as usual on November 13, with an official visit to Yorkshire.

Then, on the evening of November 13, the Queen and Duke of Edinburgh are hosting a birthday reception for their son at Buckingham Palace.

A Comedy Gala, staged jointly by the Prince's Trust charity and Carlton - and recorded in October with the Prince as guest of honour - will be televised on November 14, his actual birthday.Later, on November 19, there will be a birthday dinner and concert at Windsor Castle given by the English Chamber Orchestra, of which the Prince is patron.