Princess-to-be Kate Middleton celebrated turning 29 on Sunday, her last birthday as a commoner before her wedding in April to Prince William, the second in line to the British throne.
Clarence House, the office of William and his father Prince Charles, refused to give any details of how Middleton would mark her big day, saying only that she was spending it "privately."
British media said that Kate - who is five months older than her royal fiance - was expected to enjoy low-key festivities with her family and friends as she prepares for her April 29 nuptials.
"She will probably want to keep a low profile because the rest of her life will be high profile," said Ingrid Seward, editor of Majesty magazine, a publication focusing on the royal family.
"There are a lot of parties coming up so she might just want some really, really close friends and family with her - or it could be just her and William."
Prince William, who met Kate while they were university students eight years ago, is serving as a Royal Air Force search and rescue helicopter pilot in Anglesey, Wales.
But the couple were seen in public on Saturday at the wedding of one of William's friends, with Kate sporting a tailored black velvet coat, a black dress with a plunging sheer neckline and a jaunty black beret.
William was an usher for the wedding in the northern village of Boroughbridge of Harry Aubrey-Fletcher, a schoolmate from the prince's time at the elite Eton College, and Louise Stourton.
Kate's appearance whipped up the usual frenzy in Britain's royalty obsessed newspapers, with the Mail on Sunday saying Middleton looked "thinner than usual" and adding: "Hope you won't wear black on April 29, Kate!"
The News of the World tabloid, Britain's biggest selling newspaper, focused instead on whether or not the country's future queen was wearing a bra.
William and Kate earlier this week released new details of the plans for their wedding at London's Westminster Abbey, including that they would be married by the Archbishop of Canterbury, Rowan Williams.
They will also make a procession in a horse-drawn carriage through some of the capital's most historic sites after they have tied the knot.