Russell Crowe, Zac Efron join 'The Greatest Beer Run Ever' shoot in Thailand

The film is directed by Peter Farrelly whose 2018 film 'Green Book' won three Oscars in 2019, including best picture, reports variety.com.

The film is an adaptation of the book 'The Greatest Beer Run Ever: A True Story of Friendship Stronger Than War', written by Joanna Molloy and John 'Chickie' Donohue.

It is based on the true story of Donohue, who left New York in 1967 to track down and share a few beers with his childhood buddies in the army while they were fighting in Vietnam.

As with Spike Lee's own wartime buddy movie 'Da 5 Bloods', the production is using Thailand as a stand-in for Vietnam.

Skydance Media is producing the film for Apple TV Plus. Brian Currie and Pete Jones co-wrote the script with Farrelly.

Local coordinator Oliver Ackerman of services company Living Films is facilitating the production in Thailand.

Crowe and Efron have been visible on social media since arriving in the Southeast Asian nation, though both have been coy about naming the project.

However, a Skydance spokesman confirmed to Variety over email that "we are in production on 'The Greatest Beer Run Ever' in Thailand with Pete Farrelly at the helm".

On Twitter, Crowe said: "Australia is set to allow international travel soon. Currently I'm working in Thailand. Shooting a movie. Getting on that first plane after 2 years was a very strange feeling. Strange but kind of wonderful."

He subsequently explained that he entered the country via Phuket, where he was subjected to the country's 'Phuket Sandbox' scheme, a two-week light quarantine for fully vaccinated travelers from designated countries, and then posted pictures of himself bicycling around the sights of capital city Bangkok.

Crowe also posted images of Efron and a video of a huge water lizard. Thailand's military government was initially delighted by the star's warm comments and touristy images, but then went into a spasm of denials when Crowe posted a photo of the chaotic tangle of overhead cables that festoon most city streets.

Efron, who has also been largely Australia-based for the past two years, used Instagram to post a shirtless image of himself on a Thai beach celebrating his 34th birthday.

Thailand, which has studio facilities, skilled crews and a production rebate system, is a regular destination for international productions.

Earlier this year, it was home to Paramount Television and Apple TV Plus' 'Shantaram'. Production in studios just outside Bangkok was temporarily shut down in July when Thailand endured the peak of its third wave of the coronavirus outbreak.

However, the Charlie Hunnam-starring series is understood to have finished its Thai stint on time and on budget.