Cavill auditioned to play Bond before Craig landed the role in 2005. During his screen-test, Cavill walked out of a bathroom while wrapped in a towel and reenacted a scene from one of Sean Connery's Bond films.
"I probably could have prepared better," Cavill said. "I remember the director, Martin Campbell, saying, 'Looking a little chubby there, Henry."
"I didn't know how to train or diet," he added. "And I'm glad Martin said something, because I respond well to truth. It helps me get better."
Cavill went on to star on the Showtime series The Tudors and in the 2011 film Immortals. He adhered to a strict diet and training regime for the Immortals, which kickstarted a new dedication to fitness.
Cavill's training intensified once he landed the role of Clark Kent, aka Superman, in the 2013 film Man of Steel. He remains dedicated to fitness to this day.
"I know what it feels like to go from out of shape and [afterward] I'll look at myself like, 'Man, well done,'" he said. "It's not like I'm a golden god -- I'm just proud of what I achieved."
Cavill said he was unpopular in school and was called "Fat Cavill" by his classmates.
"I was a chubby kid," he said. "I could've very well gone down the route of just accepting my lot in life and being like, 'I guess I'm not going to do anything.'"
Cavill has played Superman in three DC movies, and said he has "a lot" to give for Superman yet. He will also star as Geralt of Rivia in the Netflix series adaptation of The Witcher, which premieres Dec. 20.