Toby Melville - WPA Pool/Getty Images
Although the milestone day isn't until tomorrow, April 21, Queen Elizabeth II will kick off her 90th birthday today and continue the celebrations over the next 48 hours.
This morning, she began the festivities by joining alongside Prince Philip and visiting a Royal Mail sorting office in honor of a new special birthday stamp featuring the Queen as well as to celebrate the postal office's 500th anniversary. Shortly thereafter, she and Philip opened a new bandstand where children sang and performed in front of them.
Later this evening we can also look forward to new, official photos of Her Royal Highness, which will be released at 7:01 p.m. EST.