The video both women are referring to is one posted to the official Prince and Princess of Wales Instagram account, where William and Charlotte shared a 'good luck' message for the English team prior to the match.
"Lionesses, we want to send you a huge 'good luck' for tomorrow," the Prince of Wales said.
"We are sorry we cannot be there in person, but we are so proud of everything you have achieved and the millions you've inspired here and around the world."
His father, King Charles II also shared a message of good luck for the team: "Good luck today Lionesses, and may you roar to victory."
Luckily, Queen Letizia stepped up on behalf of her fellow royals, greeting and congratulating each of the English players on the podium after their heartbreaking defeat.
Prior to the match, Queen posted a heartfelt message of support to her 105,000 followers on Instagram, with an accompanying video of her gushing about the Spanish team in an interview with Spain's TV1 before kick-off.
"It's a joy, and it's exciting, to be here to support the Spanish football team. They are already champions," the 50-year-old began the video.
"After accompanying the Heiress [Crown Princess Leonor] on her first day at the Military Academy in Zaragoza, the Queen and the Infanta [Princess Sofia] traveled to Madrid to catch another plane to Sydney with a stopover in Abu Dhabi. On [their] arrival they met with the Minister of Culture and Sport, Micquel Iceta," she revealed in the caption.
"Infanta Sofia is a great fan of football, a sport she has played and this same year accompanied the King [Felipe VI of Spain] in the Cup final held in Sevilla. Along with her sister, Princess Leonor, she also attended a match of the Spanish national team at the Euro Cup held last year in England."
After Spain's well-deserved 1 - 0 win, the Queen and her second-eldest daughter also joined the team on the field, the royals taking part in the post-match presentation, and even dancing merrily alongside their countrywomen as they celebrated their incredible achievement.
This of course made the absence of a British royal family member even more obvious, especially Prince William who is the current President of the English Football Association.
Royal watchers were sure the heir to the throne would make an appearance, especially considering it was the United Kingdom's first World Cup final since 1966.
They were however left disappointed, the Prince of Wales' opting to remain with his children across the pond.
After the match, the Spanish royal family took to X (formerly known as Twitter) to continue the celebrations.
"Champions! Champions! World Champions!," they penned on their official account.
"You are the best football players in the world. This is FOOTBALL and it is HISTORY!"
"Thank you, Spanish women's football team, for making all of Spain rock."