"Pacific Rim: Maelstrom," a sequel to the hit Universal Pictures mecha movie, has begun filming, sources confirm.

The follow-up to Guillermo del Toro's 2013 sci-fi blockbuster has officially begun production in Sydney, Australia, EW reported. "Pacific Rim: Maelstrom" director Steven DeKnight and lead star John Boyega confirmed through social media posts that filming is indeed underway.

In the meantime, here's everything you need to know about "Pacific Rim: Maelstrom."

John Boyega in for lead role

Charlie Hunnam, the lead star of the first "Pacific Rim" film, will not reprise his role as Raleigh Becket in the sequel. The 36-year-old actor said that while the initial script of the sequel heavily involved his character, he was ultimately crushed out as he could not commit to the movie due to scheduling conflicts.

Nevertheless, Hunnam is excited for "Pacific Rim 2," and if his future schedule permits, he might return in the third movie in the franchise.

Meanwhile, "Star Wars Episode 7: The Force Awakens" star John Boyega is filling in the lead role. According to Deadline, he will play the son of Stacker Pentecost, played by Idris Elba. Del Toro said that having Boyega as a leading man thrusts "Pacific Rim" further into a "multicultural, multi-layered world."

"It is undeniable that with all his talent and natural charm, John stands out amongst today's generation of young leading men," producer Mary Parent commented about Boyega's involvement in the sequel.

"Pacific Rim 2" cast members

Aside from Boyega, Scott Eastwood, Cailee Spaeny, Jing Tian, Levi Meaden, Nick Tarabay and Adria Arjona are also joining the cast. The same publication also reported that Rahart Adams is joining the sequel.

What is the movie about?

"Pacific Rim 2" will show the world following the defeat of the Kaiju colony. However, the monsters are not completely obliterated and some survivors still manage to cause havoc on Earth. The robotic Jaeger armies, meanwhile, will continue to fight the remaining Kaiju through the rift, which means a lot of the action will take place in Kaiju territory. Viewers may also learn more about the origins of the Kaiju and how they came on Earth.

 "Pacific Rim: Maelstrom" will premiere in theaters on Aug. 4, 2017.