為什麽叫Elvis“貓王”

I went to Graceland,Memphis last weekend, but I don't see anywhere say Elvis is known as 貓王, or King of Cat ...

Almost every Chinese who knew Elvis knew him as 貓王, why? I tried to get an answer from an old driver as well as the clerk behind the info desk, but none of them had ever heard of Elvis be a "King of Cat". They did call Elvis "King", but that was the King of Rock'n Roll.

Just curious to ask, Thank you.