Not strictly a cameo because of the length of time he's in the film. But just you try and make us take it out of this list. Tom Cruise won a whole new army of fans when he donned a fat suit and played a foul-mouthed studio boss who likes to dance to gangsta rap. Without a shadow of a doubt, he's the best thing in this film.
9. Neil Patrick Harris in Harold and Kumar go to White Castle (warning: Video below contains very strong language)
A classic example of a so-so film getting a major lift from a surprise cameo. In this case, the arrival of former teen-doc, Doogie Howser MD, completely strung-out on ecstasy and rambling on about wanting to go to a strip club. It's unexpected, and quite brilliant.
8. Alfred Hitchcock in his own films
The classic director made 37 cameo appearances in his own films, although some weren't that easy to spot. That's certainly not the case in the clip from To Catch A Thief below where Cary Grant and a woman with a bird cage are sat at the back of a bus and, guess who, is sitting to Grant's left.
7. Alec Baldwin in Glengarry Glen Ross
Baldwin's finest ever moment compacted into a powerful six minute speech where he plays a heartless salesman putting the fear of god into the likes of Ed Harris and Jack Lemmon. He arrived in an $80,000 BMW, his watch is worth more than you earn in a year and he actually has a set of brass balls. Brilliant.
6. Brad Pitt in True Romance
True Romance is a great film, of that there is no doubt. But Brad's turn as stoner room-mate Floyd is definitely one of the better moments. Two great lines: "Hey, get some beer... and some cleaning products" and "You guys wanna smoke a bowl?" to a room full of mobsters brandishing shotguns.

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