R. Kelly pays tribute to Nelson Mandela on 'Arsenio.'

Civil rights icon Nelson Mandela died on Thursday at age 95, and though news broke mid-afternoon, Arsenio Hall was still able to pay tribute to the leader on Thursday night's show. And his guest, R. Kelly, was also ready with an extremely poignant song.

Kelly actually wrote the song "Soldier's Heart" back in 2003 when it was released as a single with proceeds going to honor American veterans in the Chicago area. But on "Arsenio," they revealed that the real subject of the song was actually Mandela and that Kelly had performed the song for him in the South African's living room.

After the song, Hall asked Kelly about Mandela's reaction to the song.

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"He just nodded his head, man," Kelly said. "He was very happy and very honored. As I was to be in his presence. When I started performing the song for him on his piano, it was an unbelievable moment for me, man. As it is now."

The tribute to Mandela was a complete 180-degree turn for Kelly, who was on Jimmy Kimmel's show on Wednesday night talking about his new album, "Black Panties," and discussing what it is to be a sex genius.

The black panties may fly again another night, but on Thursday, the mood was appropriately somber.

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