The Big Bang Theory vet Johnny Galecki will executive produce the series.

National Lampoon's Christmas Vacation

The Big Bang Theory‘s Johnny Galecki is returning to National Lampoon’s Vacation, but in a much different capacity.

The actor, who played young Russell “Rusty” Griswold in National Lampoon’s Christmas Vacation opposite Chevy Chase and Beverly D’Angelo, is in early development on a Vacation TV spin-off for the HBO Max streaming service, EW has learned.

Credit: Presley Ann/FilmMagic; Everett Collection

The single-camera show is currently titled The Griswolds and will explore the family’s daily lives in the suburbs of modern-day Chicago. Tim Hobert, a writer-producer on Community and The Middle, will write the script and executive produce alongside Galecki and Holly Brown.

To reiterate, the series has not been officially ordered just yet and is in the script development stage at this point. As such, it’s unclear if Galecki himself will appear as an actor for the planned series or if any of the original Vacation franchise stars — including Randy Quaid, Juliette Lewis, and Ed Helms — will return.

Helms portrayed an adult version of Rusty in 2015’s Vacation, which acted as a sequel to the previous movies. Chase and D’Angelo reprised their roles for that film, while Christina Applegate played Rusty’s wife Debbie Griswold.

HBO Max is a bit further ahead on developing multiple other TV spin-offs for movie properties, including a Practical Magic prequel and the Grease-based Rydell High.

The Hollywood Reporter was the first to report the news.

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