Windsor, United Kingdom - Crowds of supporters gathered near Windsor Castle on Wednesday to wish Queen Elizabeth II an early happy birthday, as she marked turning 90 with the release of a photograph of four generations of Britain's royals.
Well-wishers waving British flags greeted the monarch and her husband Prince Philip as they visited a Royal Mail delivery office to commemorate 500 years of the postal service.
Two staff choirs joined a rendition of "Happy Birthday" in honour of the monarch's 90th birthday on Thursday, which she will spend at the castle in Windsor, near London.
"Ninety is a long time and she is still so active, it's amazing!" said Jane, a local well-wisher who came along with her granddaughter.
The postal service released a set of special stamps to mark the queen's birthday, including the first to feature her great-grandson, two-year-old Prince George.
The image of the grinning prince was captured as part of a portrait featuring four generations of the House of Windsor - the queen, her son and heir Prince Charles, his eldest son Prince William, and young George.
The photograph, taken at Buckingham Palace last summer, appears as a stamp sheet, with perforations around the faces of each royal to create a stamp for each of them.
Although the three adults are sitting down, George - wearing a white shirt and blue shorts - had to stand on four foam blocks to ensure his head was level with the other royals.
The queen last year broke Queen Victoria's record to become Britain's longest serving monarch. She has reigned for more than 64 years.