David Harbour is now getting ready to be hot as hell for "Hellboy," as the actor has revealed all the hard work he did in order to get in shape to play the titular half-demon anti-hero.

Harbour, best known as police chief Hopper in Netflix' "Stranger Things," takes the crown from Ron Perlman, the previous Hellboy actor. Harbour is now the new face of the protagonist in "Hellboy: Rise of the Blood Queen," and he was proud to show off his newly gained muscle mass for the role.

In a video shown by YouTube fitness channel Muscle Madness, Harbour can be seen pumping iron and sweating it off in the gym using various workout techniques and body-building equipment to change his previously pudgy physique.

On the other hand, Harbour has admitted that it wasn't as easy as it looked, especially for someone like him who was never really fond of the gym or working out. "I was a chubby kid growing up. Straight out of college, I did my first play, which I got pretty in shape for, but I let that go completely. So from about the time I was 26 years old, to about now, I haven't really been training at the gym seriously at all," said Harbour.

The actor, now middle-aged at 42, was apparently shocked at the new temporary lifestyle he had to maintain in order to stay in shape for "Hellboy." But, it seems Harbour's workout was overseen by some of the best in Hollywood, namely Don Saladino, who worked with big AAA actors like Ryan Reynolds and Scarlett Johansson for bodybuilding.

This, however, did not exempt Harbour from some of the most rigorous training regimes in his life, as he was subjected to a 10-week "Hellboy Boot Camp" which involved kettlebells, medicine balls, machine weights, dumbbells, weighted sleds, and more. This was to ensure his rapid transformation into the physically imposing Hellboy. Whether Harbour plans to continue this long after the production for "Hellboy" is over remains to be seen.

Fans will finally be able to see Harbour's new look once "Hellboy: Rise of the Blood Queen" arrives in theaters on Jan. 11, 2019.