Prince Harry is speaking openly about the mental health challenges veterans face during a panel at the Veterans’ Mental Health Conference at King’s College London on Thursday.

Harry, who served in the Army Air Corps for 10 years and was deployed to Afghanistan twice during his service, took part in a panel alongside Caroline Buckle, Philip Eaglesham and Ivan Castro, three veterans of the U.K. and U.S. Armed Forces.

The Royal shared a special moment with Castro, who was blinded and near death following a 2006 battle in Iraq, helping the veteran across the stage, according to People.  Castro fought his way back from his injuries to return to active duty and began to participate in marathons and extreme race challenges around the world.  Castro is running the Boston Marathon in support of Heads Together, the mental health charity founded by Harry, Prince William, and Duchess Kate Middleton.

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During the panel, the group of veterans spoke about the mental health challenges facing veterans.

“It is incredibly difficult to talk about mental health in the Armed Forces. It is still a very difficult conversation,” says Harry. “As a military person, once you put that uniform on during your training, you are taught to be invincible and not to let anybody down. However, a lot of individuals prefer turning to alcohol rather than a friend.”

Mental health awareness has long been a priority for both Princes Harry and William, and Duchess Kate.  Their Heads Together project aims to change the conversation and end the stigma surrounding mental health issues, particularly with veterans.

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“I am saying at this time to all the military people in this room and beyond — it is okay to have depression, it is okay to have anxiety and it is okay to have an adjustment disorder. We need to improve the conversation. We all have mental health in the same way we all have physical health,” he explains.

Later this year, Harry will be in Toronto for the Invictus Games, the multi-sport event created by the Royal in which sick or injured armed service personnel and veterans compete in a range of sports.  The games kick off in Toronto on September 23.