Kate Middleton 31st Birthday: Pregnant Duchess Through the Years [PHOTOS]

Catherine Middleton, The Duchess of Cambridge, will turn 31 on 9 January - her last birthday before being a mother.

The Duchess has impressed the world with her unique style, sporting a wardrobe of colourful dresses, basic pumps, simple jewellery and the occasional skinny jeans. And now, she has turned a household name and one of the most talked about women on the planet, gracing the pages of countless fashion magazines.

Keeping away from limelight, this year, the couple is expected to have a low-key and private birthday celebration with their family, either over lunch or dinner. The Duchess, was ordered to rest after she left King Edward VII's Hospital on 6 December, after being diagnosed with acute morning sickness. Hyperemesis Gravidarum is a "potentially serious" ailment causing vomiting and a bodily reaction against intake of food and liquids. This sickness, commonly found in pregnant women carrying twins, could last up to the 21st week of pregnancy.

The father-to-be, Prince William, is reportedly planning to gift his pregnant wife a private country house.

"They've talked about getting a place where they can get away from it all. And now Wills has narrowed down the list to a few incredible places in Hampshire and Buckinghamshire around the £5m mark. They don't want to be too close to London as they are already based in Buckingham Palace. Wills has gathered together various property details from some high-end retail estates which he will give to her on her birthday," a source said.

Meanwhile, former Spice Girl-turned-fashion designer Victoria Beckham has reportedly agreed to help the couple to welcome their first child together.

"Victoria's promised to help Kate through the pregnancy. She's keen to share the wisdom four pregnancies has given her," a source told Now magazine, adding, "Kate totally admires Victoria and what she's achieved. She also wants to be a hands-on, hard-working mum and wants to know how Victoria makes the whole thing look so effortless."

On the occasion of her birthday, IBTimes UK dedicates a photo tribute the Duchess of Cambridge through the years...