Movies are meant to transport you, taking you out of your everyday life and providing two hours of sheer escapism. The whole "leave your brain at the door" mentality that pervades the target audience of the explosion-centric films of Michael Bay and his ilk may be a little off-point (how do you go to the cinema and not look to be engaged?), but the idea of getting enraptured in the world on screen - be that a cosmic space saga or an intimate personal drama - that you forget everything else is a potent one.
So when a big celebrity rears their head in a clearly purposed hat-tip to the audience it can all be a bit surprising. There you are, absent-mindedly enjoying Hook, basking in how not as awful as Pan it is, and then all of a sudden you have Glenn Close stood about dressed as a man?! What?
To celebrate the art of the cameo, let's take a look at the most bizarre, noteworthy and frankly ridiculous examples of someone super famous appearing in a movie for a matter of seconds for no reason other than to say "Yup, it's me."