Elizabeth Banks may be taking her own walk of shame -- into a federal courthouse, that is -- 'cause she just got sued for allegedly ripping off a script for her latest movie, "Walk of Shame."
Dan Rosen claims he pitched the idea for a movie called "Darci's Walk of Shame" to Banks and her producer husband Max Handelman during a 3-hour meeting in 2007.
According to the lawsuit, after Rosen gave Banks and Handleman his script ... he never heard from them again.
Rosen says there are too many similarities between Banks' movie -- which came out May 2 -- and his story to be coincidental.
He says both works share similar characters and plot -- both are about a pretty blonde in her 30s who goes through a breakup, gets drunk and has a one-night stand with a younger man, then has to get to an important event wearing an inappropriate outfit from the night before.
In other words ... it's like every other rom-com script in Hollywood.
Rosen is suing for at least $500k ... PLUS all the profits from the movie.