American singer/songwriter Josh Groban has thanked former South African President Nelson Mandela for inspiring one of his album tracks. Groban, 26, met Mandela during a 2004 trip to South Africa and was invited to be an ambassador for the former leader's 46664 charity project. When writing his 2006 album Awake, Groban admits he used Mandela as his 'muse' for the song Weeping, which he recorded with Ladysmith Black Mambazo. He says, "He inspired me to write Weeping, a song about the end of apartheid and looking back on our mistakes. "It's relevant to the world we live in today. To have some of my South African heroes play on my album on my album was life-changing and it's one of the most political songs ever written."