PARK CITY - Ed Helms went to Las Vegas for "Hangover," but in "Cedar Rapids," he heads to a locale "like Vegas with corn": Cedar Rapids, Iowa.

And he won't be alone. John C. Reilly -- whose name has cropped up plenty throughout the 2011 Sundance Film Festival -- is headed to the Heartland, too, and for Helms, it was a cast addition dream come true.

"The Office" actor told HitFix he's a "giant" Reilly fan, and has been since seeing him perform in "True West" on Broadway with Philip Seymour Hoffman back in 2000.

"It was a coup to get him in this movie," Helms said. "All i had to do was show up and he would sort of be so good, I would have to reach his level."

He felt good about the tight script, penned by Phil Johnston, but there was room for improvisation, too. And while both Helms and Reilly boast musical talents, the former was mum on whether they'd be singing in the Miguel Arteta-helmed comedy or not.

"Cedar Rapids" premiered in Park City tonight (Jan. 23); it screens, too, on Jan. 24 and Jan. 29.