For the highly anticipated sequel to 'The Hangover,' Liam Neeson replaced Mel Gibson in the cameo role of a Bangkok tattoo artist -- after cast and crew allegedly objected to Gibson's participation -- and the scene reportedly went off without a hitch.

But as it turns out, moviegoers won't see Neeson in 'The Hangover: Part II,' after all. What happened?

First, director Todd Phillips decided on reshoots, according to Variety. However, since the comedy (starring Bradley Cooper, Ed Helms and Zach Galifianakis) opens Memorial Day weekend, he had precious little time to shoot new footage. Neeson, tied up working on a 'Clash of the Titans' sequel in London, was unavailable to re-do his cameo for Phillips, who had no choice but to re-cast the role yet again.