Jonathan Nackstrand/AFP/Getty Images

ABC News' Bianna Golodryga and Anna Wild report:

It may be the most wonderful time of year, but for the newest royal, Kate Middleton, it is also the busiest.

The Duchess of Cambridge has been out and about this week, as she prepares to spend her first Christmas with Britain's royal family.

All eyes were on her at the Sun Military Awards in London on Monday night. Standing at the side of her husband, Prince William, the Duchess of Cambridge was stunning in a black, strapless Alexander McQueen dress.

Just hours earlier, the couple attended a more traditional Christmas lunch at Buckingham Palace. It all leads up to the big Christmas weekend.

In keeping with tradition, the royal family will gather at Sandringham house, a country estate that sits on 20,000 acres of land in Eastern England. The festivities begin with high tea on Christmas Eve, followed by a formal dinner and the official opening of gifts.

"Kate will need a casual outfit for breakfast, a smart outfit and a hat for the morning church service, a dress for lunch, a cocktail dress for early evening drinks and a full-length dress for the evening meal," ABC News' royal correspondent Kate Nicholl said, describing the royal fashion trendsetter's required Christmas attire.

PHOTOS: See Kate Middleton's Best Looks

It is said that 27 royals are expected to gather for the holiday weekend. It reportedly would be the biggest British royal Christmas gathering in years.

Where would all the family members stay? Some might get less-than-choice accommodations at the estate.

Could the princesses Beatrice and Eugenie of York  - remembered for their famous fascinators at wedding of Prince William and Kate - be on the receiving end of a snub? Their mother, Sarah Ferguson, has already been publicly exiled from family events.

Or could it be the queen's granddaughter, Zara Philips, and her new husband, Mike Tindall? Tindall, a professional rugby player, recently made headlines when, while in New Zealand to play a match, he got drunk at a bar and was photographed kissing his ex-girlfriend.

Prince William and his wife will not doubt not have to worry about accommodations. And helping Middleton feel more at home with her new, royal family will be her younger sister, Pippa.

People magazine has reported that the Queen has invited Pippa, 27, to join the family for their traditional Boxing Day pheasant shoot on Dec. 26, an event normally reserved for royals only.

And a source told US magazine that Kate, William and Pippa, "will all travel together back to Bucklebury and spend the remaining days of Christmas with the other Middleton family members," following their attendance at the Boxing Day shoot.

Adding to the holiday buzz surrounding the couple is growing speculation that Middleton is pregnant with the couple's first child.

The rumors have swirled since she first refused to eat a product containing peanuts - which is considered off-limits for expectant mothers - at a charity event in Denmark, and then appeared to conspicuously hide her belly with her purse while attending a charity concert earlier this month.

ABC News' Katie Kindelan contributed to this story.