The Duke and Duchess of Cambridge and Prince Harry will attend the launch of their new campaign to end mental health stigma.
Heads Together is the biggest project they have undertaken together and will see them working in partnership with a number of charities, including CALM and Mind.
William, Kate and Harry will launch the project at the Queen Elizabeth Olympic Park in east London, where they will be joined by campaigners, beneficiaries and ambassadors from the team of mental health organisations.
The campaign is aimed at ensuring people feel comfortable with their everyday mental wellbeing, feel able to support their friends and families through difficult times, and that stigma no longer prevents people getting the help they need.
Heads Together is also the 2017 Virgin London Marathon Charity of the Year, and next year hundreds of runners will hit the streets of London to help end stigma on mental health for good.