But the 46-year-old singer hit the Arsenio stage on Thursday with a very poignant performance of "Soldier's Heart," a song he wrote especially for Mandela back in 2003.
Kelly told Arsenio Hall that he had once played the song for the revolutionary icon at his home in South Africa.
"And I sang a special song for him on his piano. I'm just blessed to know that I walked in his presence," Kelly said. "And being around him inspired me to even go further in my life in my walk and my career and everything, man. He's just an incredible power."
"He just nodded his head, man," Kelly said of his reaction to the song. "He was very happy and very honored, as I was being in his presence. When I started performing the song on his piano, it was an unbelievable moment for me, man, as it is now."
"Soldier's Heart" hit the airwaves in 2003 as a benefit single for American veterans.