Back in February, Warner Bros. confirmed that production will begin on Justice League April 11 at Leavesden Studios in the U.K., under the direction of Batman v Superman: Dawn of Justice filmmaker Zack Snyder. The studio hasn't issued an official start of production press release quite yet, and we don't know if all of the primary cast members are on the set. However, earlier today, two of the Justice League Part 1 stars, Henry Cavill and Jason Momoa, took to their respective Instagram pages, teasing their intense workout regiments to get in superhero shape for this massive ensemble. Here's what Henry Cavill had to say on Instagram.

1st week of training done. 7 days, 9 workouts and a whole lot of food! #Superman #JusticeLeague #SupermanTraining"
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The photo doesn't show much, just the actor pulling on a sturdy rope, which presumably is attached to something quite heavy. You may recall that, back in late February, the actor shared another photo which teased the "warm-up phase" for his Justice League Part 1 training, but now it's clear the "warm-up" stage is through and his full training schedule has commenced. We don't know for sure when Henry Cavill will start filming on Justice League Part 1, especially given the events of Batman v Superman: Dawn of Justice.

Towards the end of Batman v Superman: Dawn of Justice, Superman drove a Kryptonite spear into Doomsday, which weakened him enough that Doomsday was able to kill the Man of Steel before this villainous creature died. However, the final shot of Batman v Superman: Dawn of Justice showed the dirt atop Superman's casket start to levitate, hinting he isn't dead after all. Still, we don't know how long he'll stay "dead" in Justice League Part 1.

Jason Momoa actually shared a video of one of his workout sessions, set to the classic Jimi Hendrix tune "Voodoo Child. However, it's the actor's brief caption that has fans buzzing, teasing an iconic facility from the DC comic books. Take a look at what the actor had to say below.

"Coach @wfmft getting ready for the castle. Watchtower."

In the original comics, Watchtower was one of the Justice League headquarters, which was located on the moon, but recent animated movies have portrayed the Watchtower as a satellite that orbits Earth and helps defend the planet against intergalatic threats. Naturally, we don't know for sure if Jason Momoa was referencing this specific facility in his social media post, but hopefully we'll have more details as production gets under way on Justice League Part 1. While we wait for more updates, take a look at Henry Cavill's photo and Jason Momoa's video below.

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Coach @wfmft getting ready for the castle. Watchtower.

A post shared by Jason Momoa (@prideofgypsies) on