Appearing in a video shared to the Prince and Princess of Wales' official Instagram account, the eight-year-old royal wished the Lionesses "good luck" before their match against Spain, which resulted in a 1-0 win for the Spanish women's team.
"Lionesses, we want to send you a huge good luck for tomorrow. We're sorry we can't be there in person, but we're so proud of everything you achieved and the millions you've inspired here and around the world. So, go out there tomorrow and really enjoy yourselves," said Prince William.
Charlotte, who was smiling sweetly and clutching onto a football throughout the clip, then added: "Good luck Lionesses!"
Princess Charlotte was the spitting image of her mother Princess Kate in the video, rocking one of her favourite casual summer wears - a Breton striped T-shirt.
The royal fashionista was seemingly wearing an affordable high street top from Next, which was available for just £5 when it was still in stock.
The Princess of Wales' ever-growing collection of nautical striped T-shirts have become her staple uniform for a casual ensemble with the royal owning not one, but three blue-and-white striped tees.
Back in 2022, the royal attended the Sail GP in Plymouth wearing chic 'Oyster' shorts with gold buttons from Holland Cooper paired with a blue and white Breton striped jumper.
In 2019, the Princess of Wales headed to Cutty Sark in London to launch The King’s Cup competition. Kate opted for a simple, yet stylish, ensemble to announce the news and looked stunning in a nautical-inspired outfit of navy cropped trousers from L.K.Bennett, a navy and white Breton long-sleeved top and a pair of navy suede block heeled shoes.
Even back in 2015, Kate was mad about stripes. The mother-of-three was memorably pictured playing with her then-toddler Prince George during the Gigaset Charity Polo Match at the Beaufort Polo Club.
The royal debuted yet another Breton-striped tee for the summer's occasion - and it seems like Princess Charlotte is swiftly following in her mum's trendy striped footsteps!