Kelly performed "Soldier's Heart," a song he says he wrote specifically for Mandela and performed for the former South African President in 2009. It was a sweet and subtle moment from the singer, who chose to ditch his sex genius schtick for a minute to sit behind the piano and just sing from the heart.

After his performance, Kelly talked about performing the song for Mandela in his living room, saying after he finished the song the former South African President just shook his head. "He was very happy and very honored, as I was to be in his presence," Kelly explained.

Adding, "When I started performing the song for him on his piano, man, it was unbelievable, it was an unbelievable moment for me. As it is now."