Kate, as she is commonly known, is expected to step up her royal engagements in 2025 after announcing in September that she had completed chemotherapy for an unspecified cancer.
Kensington Palace has not said where the Princess of Wales plans to mark the start of her 44th year but she usually spends it surrounded by family in Norfolk.
Her husband Prince William, heir to the British throne, was regularly photographed alone last year as both Kate and his father King Charles III received treatment for the disease.
But the royal couple are set to make more appearances together over the next 12 months as they eye a return to normality, with William suggesting that an overseas trip may even be on the cards.
The princess has not taken part in an official foreign visit since she attended the Rugby World Cup in France in October 2023.
"I think hopefully Catherine will be doing a bit more next year, so we'll have some more trips maybe lined up," William said during a visit to Cape Town in November.
Catherine's birthday comes almost a year since she was admitted to hospital for abdominal surgery on January 16, 2024.
She spent nearly two weeks in the London Clinic after her operation, and was recuperating at home when she discovered that she had cancer and had to begin chemotherapy.
Her lack of public appearances sparked wild speculation online about her condition and whereabouts, which Kate finally put to bed with a video message on Instagram in March revealing her diagnosis.
She won plaudits for her openness and received an outpouring of support, but the announcement also plunged the monarchy into crisis given that her father-in-law Charles was battling the disease as well.
Catherine received further praise following the release of a new video in September, in which she said that the previous nine months had been "incredibly tough".
'Brutal' year
In a touching video that featured William and their three children -- George, 11, Charlotte, 9, and Louis, 6 -- Catherine said that she was cancer free and looking forward to undertaking more engagements "when I can".
Her gradual return to public life late last year included attending the Emir of Qatar's state visit to Britain and the annual Remembrance Day ceremonies honouring the UK's war dead.
She also visited Southport in northwest England to meet people affected by a knife attack in July that killed three young girls.
Catherine reflected on "the most difficult times" as she hosted a Christmas service at Westminster Abbey last month, which came after William described the "brutal" year as the "hardest" of his life.
Catherine, hugely popular in Britain since her marriage to William in 2011, is adored by UK newspapers, who praise her elegance and warm attitude to the public during royal engagements.
The future queen is the daughter of a flight attendant and air traffic controller who went on to make a fortune from a business supplying party items.
Catherine met William in the early 2000s at the University of St Andrews in Scotland where she studied art history, before they wed in 2011.
She is seen as a key figure in maintaining the royals' position and relevance in a changing Britain.
Her public engagements this year are likely to feature the various charities she supports in early years education.
Catherine and William may also be called upon to attend the 80th anniversary of Victory in Europe Day on May 8 and Victory over Japan Day on August 15, which mark the end of World War II.
The royal couple also have their daughter's milestone 10th birthday to look forward to in May.
