It was the wave that launched a thousand "awws".
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Princess Charlotte made her official debut on the balcony of Buckingham Palace as the Royal Family observed an RAF flypast to mark the Queen's 90th birthday.
Not that anyone was looking at Her Majesty, though.
All eyes were on the 13-month-old as she gave her first royal wave to the hoards of crowds below.
The adorable gesture sent royal watchers into meltdown, with hundreds taking to Twitter to share gushing posts about the "total cutie".
Wave after wave of military aircraft - from a Spitfire and Hurricane, made famous during the Battle of Britain, to modern fighters like the Typhoon - roared overhead with the Red Arrows trailing red, white and blue smoke to end the display.
Charlotte - sucking on a finger to combat apparent teething - took the event in her stride and acknowledged the traditional flypast of historic and modern aircraft by putting one hand over an ear as she was held by the Duchess of Cambridge.
The Duke of Edinburgh, Prince of Wales, Duchess of Cornwall, Duke of Cambridge and Prince Harry stood by the Queen who was the centre of attention in her neon green ensemble.
Her life is being celebrated this weekend as the nation pays tribute to Britain's longest reigning and oldest sovereign with formal ceremonies and carnival street parties.