10 Movie Cameos So Well-Hidden Everybody Missed Them

Move over Spielberg, you've been out-sneaked. Emma Thompson's cameo in the 2010 remake of Clash of the Titans isn't just difficult to spot, it's impossible to spot, because - and yes, this is a little bit of a cheat - she can't actually be seen onscreen.

The story of how and why this came to be is excellent though, as explained by Thompson and Luke Evans on The Graham Norton Show in 2015.

Evans - who appears in Clash of the Titans as Apollo - revealed that he and his fellow gods got quite the surprise while shooting one of their council scenes. Just before cameras started rolling, the entire cast turned around and saw Thompson, in her full Nanny McPhee garb, randomly walk onto the set. The actress was filming Nanny McPhee and the Big Bang just next door to where Clash of the Titans was staged, and had decided to pay Evans, Liam Neeson, and the rest of the gods a visit.

Thompson then went and sat on Neeson's lap, and told him "I think you've been a very naughty boy." Moments later, the crew announced that filming was about to start, and so Thompson - rather than leaving the set entirely - decided to hide behind one of the gods' thrones, and according to the actress, she's actually in one of the shots that made it into the final cut.

So, the next time you watch Clash of the Titans, keep your eyes peeled - you might just spot Nanny McPhee lurking behind Zeus' chair.