 -- Prince Harry lent his support at a conference today to help draw attention to the daunting recovery many veterans face after leaving the battlefield and reentering society.

While their physical injuries are often evident, Harry hopes to raise awareness of veterans' invisible injuries and make mental health more accessible to those who need it.

Harry, a former Apache Pilot and founder of the Invictus Games for veterans, led a panel discussion on mental health with medical experts and military members at the Veterans' Mental Health Conference at King’s Center for Military Health Research in London.

"We all have mental health in the same way that we all have physical health," Harry, 32, told attendees.

Harry, fifth in line to the British throne, launched a mental health campaign, Heads Together, last year with Prince William and Princess Kate. The campaign is focused on destigmatizing the taboo around mental health issues and encouraging people from all walks of life to open up and ask for help.

William has focused his energy on mental health among young men while Kate has been leading the charge to raise awareness among children and parents.

Harry is targeting the military community.

"Our campaign, Heads Together, is encouraging people to be more open, without the fear of judgement, prejudice or stigma," Harry said today. "It starts with a conversation either with a friend, family member or a colleague."

Harry was joined at the conference by Ivan Castro, a U.S. Army major who was blinded in Iraq, and Karl Hinett, a U.K. veteran badly burned while also serving in Iraq. The two veterans are running on Team Heads Together next month in the 2017 Boston Marathon before taking on the 2017 Virgin Money London Marathon six days later.

"During my 28 years of service, I was honored to serve with some incredible soldiers, motivational and inspirational men and women around the world, many from the United Kingdom," Castro said today. "There is a special relationship between the U.S. and U.K. troops on and off the battlefield. We have trained together. We have fought together. We have bled together and we have healed together."

Castro, who was blinded in both eyes when enemy mortar shells landed near him, joined Harry on the Walking With The Wounded expedition to the South Pole in 2013 along with other injured service members. He also has competed in Harry's Invictus Games.

"I am proud to be running alongside Karl in the Boston and London marathons next month in support of Heads Together," he said. "Two marathons in a week will hurt but we are doing this for all veterans and serving brothers who carry the weight of mental health issues every day because we believe that we all feel pressure on our mental health at some point in our lives and, when we understand this the better, we can support ourselves and each other."

Castro and Hinett turned to running as both a recovery tool and a platform for raising awareness about military mental health. They have run over 200 marathons combined as a result.