Cole, 65, died from congestive heart failure on New Year's Eve (31Dec15), and this will be the first year twins Timolin and Casey Cole will spend without their sibling.

The sisters know it will be an emotional year, but they are planning to forge ahead with their usual celebrations, which will pay tribute to their sister, mother, and father, singer Nat King Cole.

"The sadness we feel for Natalie not being with us is indescribable," Timolin tells People magazine. "But Casey and I are compelled to keep her spirit alive. She was a warrior, a trooper and a triumphal professional, as well as a courageous and vulnerable artist. We will celebrate the Christmas season just as we did with her and our older sister Carole, and with our mother and father because they will live in our hearts forever."

Timolin and Casey will gather with their husbands and children in Boca Raton, Florida on 27 December (16) to celebrate the holiday.

"Christmas is a very special time of the year for us because our family traditions are so strong," Timolin says. "We have to hear dad singing Chestnuts Roasting On An Open Fire! And mum always told us that the holiday season was her happiest time of the year because it meant that dad would for sure be home with us."

And they are planning to host a lavish dinner because Natalie loved big meals during the holidays.

"Natalie was a comfort food lover so Casey and I are preparing a huge meal," shares Timolin.

In addition to carrying on the family holiday traditions, Casey and Timolin will also continue to work with the Nat King Cole Generation Hope organisation, which provides music education to children in need.

"Natalie was my sister who left us too early," Casey adds. "But her passion for life, her art and her family will live on forever through our Generation Hope. We are excited to begin a new year of giving back and paying tribute to our family legacy."