Tom Hopper gained notoriety for flexing his acting (and literal) muscles on shows such as Merlin, Black Sails, and Game of Thrones.

Now, he's starring in Netflix's new show, The Umbrella Academy, as the beefed-up Luthor Hargreeves. We tagged along with the British-born actor to see how he bulked up to take on the new role and to check out his functional yet brutal training style.