A Music Trivia Question

Many years ago, about thirty or so, my mother and I, and a few of my sisters went to a nationally televised event at a huge auditorium out west. One of the guest performers put on one of the most powerful and moving performances I have ever witnessed. He sang one song that night. When he was finished, the entire audience, which was in the thousands, was brought to tears. I especially remember how emotionally touched my mother was.

That night, he went by his real name. His stage name, is different. He is a well known performer famous for his outlandish appearance and antics. He is an excellent piano player. He had many rock and roll hits back in the sixties. He also has had many guest appearances on television shows. Along with his music, he is also known for his great sense of humor.

The night we saw him sing, his appearance was of a middle age African American male, with short hair and wearing a plain black suit. He looks and sounds completely different when he is in his other role. Who is this man?