Britain's Prince Harry sent out his first tweet Thursday and it was posted to the @InvictusLondon account. Hope everyone will get behind #invictusgames. Great opportunity to support and thank the men and women who have given so much. Harry— Invictus Games 2014 (@InvictusLondon) May 15, 2014 The 29-year-old royal typed the message on an iPad at an event at London's BT Tower to promote the Invictus Games, Paralympic-style competitions for injured service members. "That's why I joined the army -- I can't type fast," he joked, referring to the speed at which he dashed off the message.