The wrong kind of cameo has the ability to break the illusion of cinema - think of Tarantino turning up at the end of Django Unchained for a few lines, and it's easy to recall those times when a cameo didn't quite gel. One of the worst (and rather recent) offenders of this trope, then, occurs in slavery epic 12 Years A Slave, where Brad Pitt's carpenter character, Samuel Bass, turns up in the last half an hour to chat with protagonist and captive Soloman Northup (Chiwetel Ejiofor). There are a few problems inherent to this sequence. Firstly, when this character turns up, we're treated to the first and only "stagey" scene in the movie - one that feels more like a lecture than a natural progression, as Bass discusses the moral issues with slavery with Michael Fassbender's brutal plantation owner. Secondly, because Brad Pitt is in the film for less than 10 minutes, his prescene is inherently distracting. It's too late for Brad Pitt to make a "serious cameo" at this point. Thirdly, Pitt's character is the only truly "nice" white character in the movie. The fact that he's played by Brad Pitt... well, it just all seems a little too convenient and awkwardly messianic.
