Rolling Stone magazine reported that Murphy turned them down. Norm MacDonald, former host of Weekend Update, stated;
“Murphy knew the laughs would bring the house down. Eddie Murphy knows what will work on SNL better than anyone. Eddie decides the laughs are not worth it. He will not kick a man when he is down”
Maybe this is why we barely saw Murphy on the special.
When Cosby heard Murphy said no, he released a statement thanking Murphy and appreciating his actions.