Director Michael Bay and actress Megan Fox's feud started in 2009, when the latter gave an interview regarding Bay on set of the Transformers films.
"He's like Napoleon and he wants to create this insane, infamous mad-man reputation. He wants to be like Hitler on his sets, and he is. So he's a nightmare to work for," Fox famously said.
Bay didn't react too well upon reading these quotes and he, along with producer Steven Spielberg, fired her from the third installment of the franchise, bringing in Rosie Huntington-Whiteley instead. This led to further animosity between the pair in the months that followed, with Bay saying:
"She says some very ridiculous things because shes 23 years old and she still has a lot of growing to do. You roll your eyes when you see statements like that and think, OK, Megan, you can do whatever you want. I got it.' Nobody in the world knew about Megan Fox until I found her and put her in Transformers.'"
As with numerous feuds on this list, it seems the two have now kissed and made up (Fox starred in the Bay-produced Teenage Mutant Ninja Turtles), but it was clearly a very hostile relationship at the time. Still, don't rule out rumours of further rifts between the pair in the future.
