The royal family is speaking out against the stigma surrounding mental illness.In a new PSA , Kate Middleton, Prince William, and Prince Harry advertise a fundraising effort by the Royal Foundation and several mental health charities for the 2017 Virgin Money London Marathon.The Heads Together campaign, which aims to encourage conversations about mental health, was named the marathon's Charity of the Year.In the video, Kate reminds viewers that "mental health is just as important as physical health" while wearing a headband that reads "#headstogether.""We can play our part by talking and listening to each other and helping each other find support," says Harry.William adds, "Let's get our heads together and change the conversation on mental health."This is a cause near and dear to the royal family's hearts. Earlier this year, Middleton appeared in a similar video encouraging children to discuss their problems with a counselor for Children's Mental Health Week.Hopefully, efforts like these will help people overcome shame associated with mental illness. As Kate says, taking care of our minds is just as important as taking care of our bodies.