Heather Graham and Justin Bartha will be having a major hangover as they have joined the cast of The Hangover, an upcoming thriller from Warner Bros. and Legendary Pictures.

The film will tell the story of three friends who lose their best friend at his bachelor party in Vegas just 40 hours before his wedding. They attempt to retrace their bad decisions from the night before and figure out where things went wrong.

Graham will play a Vegas local who crosses paths with the guys and might know more about the groom than she lets on.

The film is being directed by Todd Philips and will start production this week in sin city.