Revered physicist PROFESSOR STEPHEN HAWKING was unhappy with his cameo role in hit US animation The Simpsons because he wasn't the same shade as other characters.

The A BRIEF HISTORY OF TIME scientist played himself in the episode DON'T FEAR THE ROOFER, which was aired in America in May (05).

But he complained to British chat show host Richard Madeley that he hated the way he'd been drawn compared to Homer and family.

Madeley says, "He seems to be p**sed off - but in a nice way.

"I think it was because they didn't make his face as yellow as all the other characters."