Got the odd celebrity autograph gathering dust in your loft? It could be worth a fortune... though in some cases, it could be a forgery.

From royalty to rock stars, and from the living to the long-dead, these autographs of the rich and famous can sell for big money. 

Based on Paul Fraser Collectibles' PFC40 Autograph Index, read on to discover which autographs are worth the most money – and get the experts' top tips for ensuring that you never fall for a fake. All dollar amounts in US dollars, unless otherwise stated.