The Queen will mark her 90th birthday by undertaking two engagements in Windsor with the Duke of Edinburgh. Her Majesty will meet locals and well-wishers during a walkabout in the town, after unveiling a plaque marking The Queen's Walkway at the foot of Castle Hill.
The walkway is a 6.3km walking trail which connects 63 points of significance in the town of Windsor. It was designed by The Outdoor Trust to symbolically recognise the moment that The Queen became Britain's longest reigning monarch after more than 63 years on the throne.
The Queen will carry out two engagements in Windsor on her 90th birthday
In the evening the Queen will be accompanied by Prince Philip, Prince Charles and the Duchess of Cornwall at a beacon lighting ceremony to celebrate her milestone birthday.
THE QUEEN'S 90TH BIRTHDAY: 90 REASONS TO SALUTE HER MAJESTY
Her Majesty will light the principal beacon, and a further 1,000 beacons will be lit across the country and worldwide in honour of the Queen's 90th birthday. Members of the Army Cadet Force will even take beacons to the top of the four highest peaks in the United Kingdom – Ben Nevis, Scotland; Mount Snowdon, Wales; Scafell Pike, England, and Slieve Donard, Northern Ireland.
Prince Philip, Prince Charles and the Duchess of Cornwall will join the Queen for a walkabout
They are not the only official engagements the Queen has planned in the week leading up to her birthday. On Wednesday, the day before her special day, the Monarch will once again be accompanied by the Duke of Edinburgh for a visit to the Royal Mail Windsor Delivery Office, to mark the 500th Anniversary of the Postal Service.
As well as meeting representatives from Royal Mail, the royal couple will view a demonstration of mail sorting before unveiling a plaque to mark the visit.
They will then visit Windsor's Alexandra Gardens, where they will officially open the new Bandstand and meet children from six local schools who have been involved in designing commemorative plaques for the project, before watching a short performance from a children's choir.
While the Queen's birthday will be fairly low-key, a number of other events have been planned to commemorate her milestone day in the following weeks, including four nights of celebrations in the grounds of Windsor Castle in May.