LONDON (REUTERS) - Princes William and Harry will pay tribute to their mother Princess Diana on Wednesday (Aug 30), a day before the 20th anniversary of her death.

They will meet representatives of the charities Diana supported at Kensington Palace, their current home and where their mother lived until she was killed in a car crash on Aug 31, 1997.

Two decades later, Diana is once again front page news.

Fresh revelations about her life and a raft of TV documentaries have sprung up around the anniversary.

William and Harry contributed to some of the documentaries to honour her memory but are otherwise marking the occasion more discreetly than in previous years. On Thursday, they will reflect on their mother's life in private.

The day before, they will take a tour of one of Kensington Palace's public gardens, transformed temporarily in memory of Diana. White English roses and forget-me-nots were planted in the area, renamed the White Garden, in tribute to the princess.

The palace's head gardener and a gardener who knew Diana from her frequent visits to the spot, usually known as the Sunken Garden, will explain the design and point out some of the princess's favourite plants.

Outside the palace, Britons left flowers of their own on Tuesday. Photographs and messages had been attached to its front gates as the public paid their respects, although in far fewer numbers than immediately after her death.

The vast outpouring of grief that followed the night Diana's limousine crashed in a Paris tunnel stunned many Britons, known for their stiff upper lip.

After touring the garden, the princes will meet representatives from causes Diana had supported, including Great Ormond Street Hospital, the National Aids Trust and The Leprosy Mission.