January 09, 2013 - 09:06 GMT hellomagazine.com Kate Middleton pregnant: Duchess of cambridge celebrates 31st birthday privately with Prince William Kate Middleton marked her 31st birthday on Wednesday, but celebrations were low key for the expectant royal, who is thought to be just over 12 weeks pregnant with her and Prince William's first child. St James Palace has said the Duchess of Cambridge will be spending her January 9 birthday "privately" with William. It's thought the couple will be at their home in Anglesey, North Wales where the Prince works in his capacity as an RAF Search and Rescue helicopter pilot. A romantic meal may be on the cards, or even a stroll with the couple's Spaniel Lupo. They may also be visited by the Middletons – Kate's parents Carole and Michael, and siblings Pippa and James. The royal's brother James may be the one supplying her with the birthday cake – as he runs the Cake Kit Company. Kate, who has been suffering from hyperemesis gravidarum, will no doubt welcome some quiet time at home. The elegant brunette has been spotted out and about in the New Year, at a petrol station and a supermarket, suggesting that she may be over the worst of her morning sickness. This could possibly be Kate's last birthday spent in North Wales. If her husband decides not to renew his three-year contract with RAF Valley, he and Kate will have to move out of their home by the sea this summer. Although they'll miss their much loved Welsh hideaway, a move would put them nearer to their families. Next year could be spent with their new baby in Kate and William's new home – Apartment 1A in Kensington Palace – which is currently being renovated. It was once the home of Princess Margaret and has remained unused since her death in 2002. It has required new plumbing, extensive rewiring and the removal of asbestos. As renovation work nears completion, Kate will be able to begin choosing paint colours and furnishings for all 20 rooms, including the nursery. William will turn 31 on June 21, and his celebrations are likely to be even quieter, his birthday being so close to the royal baby's due date.