Though movie cameos are often disposable and self-indulgent moments intended to generate a cheap laugh or give an A-list actor an easy paycheck for a few hours' work, when they're truly inspired, they can leave an indelible mark on a movie that people will never forget.
The best cameos prove that there's a sure art to getting them right, be it surprising audiences with an unexpected face arriving totally out of nowhere, or perhaps hiding a much-loved actor in plain sight with a clever disguise, with viewers only learning of their presence in retrospect.
These 19 cameos were met with rapturous audience responses the world over, and whether or not the rest of the movie was actually any good, these scenes have nevertheless lived on in adulation ever since.
From blink-and-you'll-miss-it appearances to surprisingly elaborate and lengthy sequences, these are the cameos that show everyone else in the industry how it should be done...
Perhaps the only really great scene in the Marvel Cinematic Universe's most boring movie to date sees Thor (Chris Hemsworth) reluctantly relying on the help of Loki (Tom Hiddleston), who cheekily transforms into an Asgardian guard, before turning Thor into Sif (Jaimie Alexander) and telling him he looks "ravishing", of course.
The gag reaches its terrifically unexpected apex, though, when Loki transforms himself into Captain America, giving Chris Evans a few moments to play Loki-As-Cap, while Tom Hiddleston's voice quips, "Costume's a bit much, so tight. But the confidence, I can feel the righteousness surging!"
Considering how most of the standalone MCU movies don't feature appearances from other Avengers, this was a neat little treat that went down a storm.