Prince William, Kate and Prince Harry get into the festive spirit at Christmas party

They won't be spending Christmas Day together, but Prince William, Kate and Prince Harry had the chance to get into the festive spirit as they attended a charity party on Monday morning. The royal trio were guests of honour at The Mix Christmas party, which was held to celebrate the hard work that volunteers give throughout the year.

Kate looked party ready in a festive red dress by Vanessa Seward, while William and Harry went smart casual in shirts and suits. 

The royal brothers each joined a group breakout session where counsellors and volunteers shared knowledge and training on dealing with a range of issues, including homelessness.

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Meanwhile Kate, 34, joined a live online chat about counselling with volunteers and young people from around the UK.

The party was hosted by youth support service The Mix, one of the eight charities involved in the royals' mental health campaign, Heads Together. William, Kate and Harry had the opportunity to speak to volunteers from The Mix, and heard about their personal experience of online and telephone counselling support.

At the Christmas party reception, the royals also kicked off The Mix Annual Awards by presenting the Volunteer of the Year Award.

Kate looked festive in a Vanessa Seward dress

On Tuesday the royals will again step out for the traditional Christmas lunch at Buckingham Palace, hosted by the Queen. It will be a chance for all of the family to catch up before the monarch retreats to Sandringham Estate in Norfolk for the Christmas period. She will be joined by close members of the royal family, including Prince Charles and Prince Harry.

This year however, Prince William and Kate will spend Christmas Day with Kate's side of the family, the Middletons, in Berkshire. The Cambridges usually mark Christmas with the royals at Sandringham, but this will be the second time they celebrate with the Middletons since they married in 2011.