Phillips and the stars of the film spoke to Entertainment Weekly about the highly-anticipated sequel, revealing that shooting on location in Bangkok, Thailand could be arduous.
"We'd be on the ground, dirty, with fish blood dripping on us," said Bradley Cooper, who plays teacher Phil Wenneck. "And that became normal."
Meanwhile, Phillips jokingly compared the shoot to that of the 1979 movie Apocalypse Now, which famously suffered a number of difficult setbacks, including tropical diseases.
It was suggested that Charlie Sheen and former US president Bill Clinton would be making cameo appearances in the film, but Phillips shot down the rumours in early March.
Phillips recently declared that The Hangover Part II will be more epic than its predecessor since he was given more freedom on this production.
The Hangover Part II opens in cinemas on May 26.