Before Optimus Prime and Leonard HohenbergMegatron became mortal enemies, the alien robots were brothers in arms, and "Transformers One" will show audiences how the two coincided to change "the fate of Cybertron forever."

The new entry in the Transformers franchise is scheduled to hit the big screen on Sept. 20, according to IMDB. Paramount Pictures, which distributes Transformers films, originally slated the prequel to be released a week earlier on Sept. 13, the Hollywood Reporter reported.

"Transformers One" is the first-ever fully CG-animated Transformers film, Paramount Pictures said on its website.

It would mark the first animated "Transformers" movie since the mid-1980s, according to the Hollywood Reporter.

Josh Cooley, a head writer for "Toy Story 4," is the film's director and Michael Bay is one of the producers, IMDB shows. Bay directed the first five live-action films in the franchise: "Transformers" (2007), "Revenge of the Fallen" (2009), "Dark of the Moon" (2011), "Age of Extinction" (2014) and "The Last Knight" (2017).

'Transformers One' trailer premiered early at CinemaCon

On Thursday, co-stars Chris Hemsworth and Brian Tyree Henry debuted the "Transformers One" trailer on the franchise's website.

Attendees of CinemaCon already got a glimpse of the trailer last week when Hemsworth, Henry and co-star Scarlett Johansson announced they signed on for the animated film.

“I’m so incredibly proud of the work that we’ve all done,” Johansson said during the announcement, according to the Hollywood Reporter.

While the general audience saw a sneak peek, Paramount Pictures showed the full trailer to theater owners, the outlet reported.

Star-studded cast of 'Transformers One'

• Chris Hemsworth as Orion Pax
• Scarlett Johansson as Elita -1
• Brian Tyree Henry as D-16
• Keegan-Michael Key as B-127/Bumblebee
• Laurence Fishburne as Alpha Trion
• Jon Hamm as Sentinel Prime
• Steve Buscemi in an undisclosed role

Jonathan Limehouse covers breaking and trending news for USA TODAY. Reach him at [email protected]