Duchess Kate Celebrates 34th Birthday

— -- The Duchess of Cambridge will celebrate her 34th birthday Saturday in Norfolk, England, at her Anmer Hall home with Prince William.

Kensington Palace has not released any information about Kate's birthday plans other than to say it will be a "private celebration." Kate's sister and brother, Pippa Middleton and James Middleton, just returned from a holiday in St. Barts on Thursday so it is likely Kate will share her birthday at some point with them.

It has been a busy year for Kate with the birth of her second child, Princess Charlotte Elizabeth Diana, in July, and her older child, 2-year-old Prince George, starting his first day of nursery school this week with his proud parents there for the big milestone.

Prince George will spend several days a week at Westacre Montessori school with other local children. William and Kate will continue to split their time between Kensington Palace and Norfolk but the royal couple hopes their children can spend time away from the public eye, allowing George and Charlotte to grow up away from the spotlight while experiencing the joys of childhood.

It seems like only yesterday the world watched as Prince William married Kate in Westminster Abbey. This year, 2016, will see the couple celebrate their fifth wedding anniversary and the anniversary of the Royal Foundation of The Duke and Duchess of Cambridge and Prince Harry.

Last year was a busy one for Duchess Kate as she took on an increasingly high-profile role in the royal family. Kate attended her first state banquet honoring the Chinese President Xi Jinping. Kate looked ravishing at the October event, wearing a red gown in a nod to the Chinese, and the Lotus Flower tiara as she toasted with China's president.

Weeks later, Kate drew comparisons to her late mother-in-law, Princess Diana, when she debuted the Cambridge Lovers Knot Tiara at the diplomatic reception hosted by Her Majesty the Queen. Kate also last year visited a women's prison where inmates have successfully conquered their addiction issues in a pioneering new program to help those with drug and alcohol problems.

The duchess also upped her profile on the philanthropic front, juggling motherhood with a busy schedule focusing on issues close to her heart, including arts, education, substance abuse, counseling and addiction and mental health.

Royal sources told ABC News that 2016 will see the duchess continuing to raise awareness on childhood mental health. She returns to royal duties at the end of January and, in February, will work with her charity, Place2Be, during Children's Mental Health Week in the U.K. Kate is Royal Patron of the charity and has been seeking to end the stigma for children suffering from mental health issues.

Duchess Kate is also expected to add a few royal patronages to her portfolio from other members of the royal family. The duchess has 12 royal patronages and it is anticipated she will expand that to reflect her personal philanthropic interests.

Kate is royal patron of the 1851 Trust and 2016 will see Kate supporting the British sailing team, led by Sir Ben Ainslie, trying to bring the America's Cup back to the U.K.

Later this spring, William and Kate will travel to India and Bhutan, their first royal tour abroad since their trip to New York in December 2014. Prince George and Princess Charlotte will not join the week-long tour with their parents.

There could be another royal tour in the fall of 2016, which might be an opportunity for Prince William and Princess Kate to be accompanied by their children.

Of course, the biggest milestones will take place at home away from the cameras. Princess Charlotte will take her first steps. Prince George will celebrate his third birthday in July and Charlotte’s first birthday is coming up in May.

We know the duchess has introduced the exuberant Prince George to the Buckingham Palace swimming pool and he will no doubt be riding a pony soon enough. But as baby Charlotte grows, she too will enjoy the warm childhood environment William and Kate have created for their children in London and Norfolk.

Kate, a keen photographer, has done double-duty snapping family photos and sharing them with the public this year, and she will do more of the same in 2016.

Perhaps the biggest role Kate will play in 2016, aside from the role of wife and mother to two future kings of England, will be celebrating Queen Elizabeth’s 90th birthday and Prince Philip's 95th birthday. William and Kate, along with Prince Harry, will participate in the multiple parties planned to commemorate the milestones.