Although I would have preferred to see Anthony Michael Hall back in the role, it seems like Ed Helms will be the next actor to portray Rusty Griswold in the new sequel/reboot
Vacation.
Helms will play Rusty Griswold, the son of Chevy Chase in the original films. Ed Helms is in negotiations to star in New Line's planned Vacation reboot. Helms will play Rusty Griswold, the kid from the original films, who in the new movie will be all grown up and embarking on a vacation with his own family. John Francis Daley and Jonathan Goldstein are directing the project, which plays like both a sequel and a reboot of the Chevy Chase franchise that began with the 1983 Harold Ramis-directed comedy National Lampoon's Vacation. That film was written by John Hughes based on his own experiences on family vacations. Anthony Michael Hall played Rusty in the original. The franchise continued with European Vacation (1985), Christmas Vacation (1989) and Vegas Vacation (1997). The new project will start lensing in the spring after Helms wraps The Office. David Dobkin is producing. Helms, repped by CAA and Principato Young, is in production on Lionsgate’s They Came Together with Paul Rudd and Amy Poehler and will begin shooting The Hangover Part III in September.
Source:
The Hollywood Reporter
