The Queen and members of the Spencer family will gather in Hyde Park tomorrow for the official unveiling of the Diana, Princess of Wales Memorial Fountain.

The opening ceremony of the Diana fountain is said to be the first such public appearance for the Royal family and Diana's brother Earl Spencer, who criticised Buckingham Palace at her funeral in 1997.

The Queen will speak at the ceremony and is expected to pay tribute to Princess Diana, who died after a car she was travelling in hit the wall of a tunnel in Paris.

Princes William and Harry will also attend, along with a select group of guests.

Members of the public will be lucky to get a peek of the fountain and memorial gardens, with Royal Parks warning of large queues tomorrow, when the area will be open for limited access.

The Diana memorial fountain, built at a cost of £3 million, will be open to the general public on Wednesday.

The fountain features a massive oval waterway, with water running in both directions before meeting in a 'Reflecting Pool'.

The water channels flow around the edge of gardens and landscaped grounds.