LONDON (REUTERS) - A mental health charity's Christmas party was lent some royal star power on Monday (Dec 19) as the Duke and Duchess of Cambridge and Prince Harry joined in and helped make decorations.

After attending the annual general meeting of the Heads Together charity in London, the royal trio chatted to volunteers at phone helpline The Mix's festive bash, celebrating those who help support people through tough times.

The Mix gives young people aged 13 to 25 a helping hand to find their way through any challenge, from homelessness to finding a job, from money to mental health, from break-ups to drugs.

The Duke and Duchess of Cambridge and Prince Harry helped decorate baubles, make paper chains and create gingerbread houses.