Why do people think this? They don't look alike - the only thing they have in common is the red hair, but Hewitt's is wavy, whereas Harry's looks like a loo-brush, not at all dissimilar to Earl Spencer's.
Plus - wouldn't one of the tabloids have swiped a hair off his jacket while rolling out of a club at 3 in the morning, had it analysed and flogged the story by now if there anything even remotely in it at all.
I always think people are a wee bit simple/naive when they trot out this old chestnut. 