The veteran actor will star in the Walt Disney live action film Pete's Dragon, which will be shot in New Zealand next year.
The West Otago township is one of several locations to feature in the remake of the 1977 Disney classic, and is set to undergo its own Hollywood makeover.
The town's 750-strong population is expected to swell by hundreds when shooting begins in April.
Redford (78), an Academy Award winner, who has starred in such classics as Butch Cassidy and the Sundance Kid, The Sting and The Great Gatsby, is expected to spend 10 days in the township.
Tapanui was buzzing about the news yesterday, and that will be amplified today with locals having a chance to be cast as extras in the movie.
Resident Gill Tuckey says she did not know what to expect when a dozen people showed up in her main street shop, Tuck's Pantry, three weeks ago.
She soon learned they were film scouts looking to see if Tapanui could be made to resemble a town in Oregon, United States, circa 1982.
''First week they came, they looked around, they talked to business owners ... they took heaps of photos,'' she said yesterday.
Residents were told ''we should know sooner or later ... and then bang! It's approved.''
Fellow resident Zita Young was also excited.
''It's not too often you hear about Disney coming to a town like this. It will be great bragging rights.''
She would join her three children at the casting call in town today.
''Everyone's talking about it. It's not just kids - they're looking for a wide variety [of people].''
Filming will include six days at the decommissioned sawmill, formerly Blue Mountain Lumber, about 15km out of town, and the main street is expected to be closed for four days.
After their first visit, the film crew returned with director David Lowery, who also co-wrote the script.
He tweeted pictures this month of a New Zealand forest as part of the film's ''tech reccy day''.
John McKeown, owner of Seasons, which houses the NZ Post outlet in Tapanui, has already had some good news.
He has been told to expect a fresh paint job on his store before filming begins, so it matches an American street of the era in which the film is set.
He might even keep the ''memento'' after filming ends: ''If they've done the prep right ... we'll see,'' he said.
''It'll help beautify the town.''
The news Redford was coming to Tapanui was met with disbelief, but the women of the town were excited by the prospect, Mr McKeown said.
He believed the filming would have a lasting impact on the town.
Walt Disney Studios last month announced production of the movie would be based at Stone St Studios, in Wellington, and create 400 jobs.
Another 400 people would work at other film locations, including Bay of Plenty, Canterbury and West Otago.
Film New Zealand confirmed it assisted the Hollywood studio in assessing New Zealand for the production.
Producer Barrie Osborne, who worked on the Lord of the Rings films, said ''New Zealand has long been a wonderful partner for film production, and in particular Wellington's state-of-the-art facilities and film-maker-friendly community make it an ideal location for filming Pete's Dragon.''
Film Otago Southland chief executive Kevin Jennings, speaking from China, said ''it is fantastic to see a film of this calibre shooting in the South Island''.
''It is a great opportunity for Otago to feature on the global stage, where the offerings of the region support the world-class infrastructure in Wellington.
''It is exciting to see the positive benefits a production like this can deliver to Tapanui.''
