“ This is soul diva Alicia Keys before she was famous bouncing on Bill Cosby’s knee . The Empire State Of Mind singer was just four-years-old when she appeared on the Cosby Show with the comic legend who played family man Cliff Huxtable. Keys had just a brief appearance on screen as she took part in a sleepover with pals of the Huxtables’ daughter Rudy. Speaking of her appearance on the U.S. show, Keys said: ‘It was a really, really good memory for me. The whole cast was so cool. We would sit on that big, huge couch and stuff and we all had to sit on Cosby’s knee. He always tried to knock us off of his knee with the bucking horse thing. Of course, my favorite part was winning the game, because I was the winner.” ( 2 minute 41 seconds .) Slumber Party , Season 1 Ep. 22