The Royal Family’s official Twitter and Instagram accounts shared a post on Monday to celebrate Kate, who turned 41 on 9 January.
“Wishing The Princess of Wales a very Happy Birthday today!” they wrote, along with a birthday cake emoji.
The post also included a photo of Kate during her first visit to Wales in September after she and Prince William were named the Prince and Princess of Wales. In the image, she could be seen accepting a bouquet of flowers from a young child.
Kate also received tributes from other UK-based military groups and charities that she has notably been a part of. The Royal Air Force Air Cadets reshared King Charles and Camilla’s post, before adding their own message.
“Wishing our Royal Patron and Honorary Air Commandant of the Royal Air Force Air Cadets, the Princess of Wales @KensingtonRoyal a very Happy Birthday today,” the cadet organisation wrote.
Some of the children’s organisations Kate has worked with also celebrated her, including mental health charity Place2Be.
“Thank you for your support over the past 10 years, and for your ongoing commitment to improving children and young people’s mental health and wellbeing,” the page tweeted.
This morning, Westminster Abbey’s Twitter page shared a video of the church’s bells chiming in honour of the Princess.
“The Abbey bells are ringing to celebrate the birthday of The Princess of Wales,” the official wrote, along with a red balloon emoji.
These birthday tributes arrived just one day before Harry’s release of his memoir, which is said to feature major revelations about his relationship with the royal family. Kate’s birthday also arrives as Harry has been taking part in many interviews to promote the book, including one on Sunday 8 January with Anderson Cooper for CBS’ 60 Minutes.
On 9 Monday, Harry also spoke about William and Kate during an interview with Good Morning America’s Michael Strahan. To Strahan, Harry claimed that British tabloids have pitted the couple against him and his wife, Meghan Markle.
“They pitch the Waleses, which Kate and William are now, against the Sussexes, me and my wife,” he said. “They always pitched us against each other. They pitch Kate and Meghan against each other.”
When Stahan asked if he thought this then made the two women “go against each other”, Harry said “without question”.
In a widely publicised recent ITV interview with Tom Bradby, Harry also said that he felt like a “third wheel” after his brother married Kate.
“I had put a lot of hope in the idea that it’d be William and Kate and me and whoever,” he explained. “I thought the four of us would bring me and William closer together… we could go out and do work together, which I did a lot as the third wheel to them, which was fun at times but also, I guess slightly awkward at times as well.”