Mills won gold at Rio 2016 and silver at London 2012 in the 470 class alongside Saskia Clark, and will now go for gold with teammate Eilidh McIntyre.
She was named alongside rower Moe Sbihi, who won gold in the coxless four in Rio and bronze in the men’s eight in London.
It’s the first time that nations have been allowed to nominate one female and one male athlete as flagbearers. Mills will be the first female British sailor to carry the Union flag at an Olympics opening ceremony.
McInytre, with whom Mills won the 2019 470 World Championship, will share the moment with her teammate as one of just a handful of British athletes who will march behind the flagbearers tomorrow evening.
The announcement by Team GB Chef de Mission Mark England was met by rapturous applause from Mills’ fellow athletes.
“Getting to carry the flag for Team GB at the Opening Ceremony of the Olympic Games is not a sentence I ever thought I’d say,” said Mills, from Cardiff.
“When Mark told me I had been chosen, it was completely overwhelming and when I had a moment to think about what it meant I got pretty emotional.
“It is the greatest honour in my career and I hope more than ever before, this Games can lift our country and deliver some incredible sporting moments to inspire the nation.”
Mills and Sbihi were selected from a group of athletes nominated to Team GB by sports. The nominees were chosen by their respective sports as athletes that exemplify the Olympic Values and uphold the Team GB values of pride, responsibility, respect and unity.
England added: “Having spoken personally with Hannah and Moe, it was clear to see what this honour meant to them. Not only what it meant personally, but also for their teammates and wider delegation in what has been the most difficult and unprecedented 18 months for everyone in the United Kingdom.
“Both athletes embody the Values of Team GB and they are thoroughly deserving of this great honour. Hannah and Moe have already created multiple Olympic memories and I have no doubt they will add to these in Tokyo over the next 16 days.”
The news comes as a timely boost to the sailors of Team GB as they prepare to take on the world’s best on the waters of Enoshima, the same venue as the sailing competition at the 1964 Tokyo Olympics, across the ten Olympic classes.
Racing starts on Sunday July 25 with men’s and women’s RS:X windsurfing plus the Laser and Laser Radial singlehanders, and concludes on August 4 with the medal races for the men’s and women’s 470.
For a full guide on how to follow the sailing action at Tokyo check out the British Sailing Team’s dedicated Olympics page here.
For full results and the competition schedule, please click here.