Formal celebrations for the Platinum Jubilee began with Trooping the Color, an annual military review that has marked the sovereign's official birthday since 1760.
The queen is expected to join the working members of her family on the balcony of Buckingham Palace at the end of the event, when 70 aircraft are set to roar overhead.
The 96-year-old queen is Britain's longest-reigning monarch and the first to reach the milestone of seven decades on the throne. The jubilee is giving many people - even those often indifferent to the monarchy - a chance to reflect on the state of the nation and the huge changes that have taken place during her reign.
"You are our friend, such a close ally, our example of service to others," Macron told the queen in an English-language video message. Each year a different unit has the honor of trooping its color. The 1st Battalion of the Irish Guards will have the spotlight during the Platinum Jubilee. "You're never going to see this again in your lifetime," she said."At least not in mine, maybe not in my daughter's. ... Seventy years -- it is all I have ever known."