Filmed in secret.
This "film" was actually a very intricate Superbowl LII ad to promote Australian tourism.
The film franchise is inspired by real-life Australian Buffalo Hunter/Cattle Grazier Rod Ansell. Who, through his wife, Joanne Van Os, is the Uncle of the acting trio of brothers Luke, Liam, & Chris Hemsworth.
This film's director is named Steve Rogers, the identity of the very famous superhero Captain America, aka Steven G. "Steve" Rogers, from the Marvel Comics as well as the Marvel Cinematic Universe (MCU). Who teams up with numerous others (i.e. Hulk, Hawkeye, Iron Man, Black Widow) who, much like him, posses great powers needed to protect the planet from potential invading outside forces in the Avengers (2012). One of them includes Thor, the Hammer-wielding Asgardian god of Thunder-Lightning, who is portrayed be Chris Hemsworth, but originally pursued by his brother Liam.