Cavill recalled being a Superman fan as a child growing up on Jersey, in the British Channel Islands.
"I was a kid running round the garden with a tea towel round his neck, beating up his brothers and stuff," he told AFP ahead of the film's release in the United States this week and around the world over the rest of June.
The 30-year-old was once dubbed "the most unlucky man in Hollywood" after losing out to Daniel Craig to become James Bond in 2005, and just failing to be cast in 2006's "Superman Returns".
But he finally got the call from seasoned action/sci-fi director Zach Snyder to play a character famously portrayed by Christopher Reeve in four movies from 1978 to 1987, before he was paralyzed in a horse-riding accident.
Preparing for the role involved five months of grueling physical training and specialized diets to build muscle mass while maintaining a lean physique, fully on display in the movie.
"Throughout the movie we did some fine tuning, some sculpting, and then one very intense leaning period six weeks during the movie for the shirtless stuff," he said, referring to scenes before he dons the famous Superman suit.
Perfecting the US accent also took weeks of work with a voice coach to transform his English public school vowels into Midwest twang.
His Oscar-nominated co-star Adams, making her first major blockbuster movie, was impressed both with his accent -- "it's pretty close to perfect" -- and his acting skills.
"He has a physical presence as Superman... but then has this beautiful vulnerability and gentleness to him," she told AFP -- while admitting that kissing Superman, near the film's climax, was less fun than some might think.
"People are always so disappointed when they find out the truth (that) kissing scenes are always so technical. But you know, it's all in a day's work, for a working lady," she joked coyly.
The movie is packed with spectacular special effects, as Superman socks it out with the evil General Zod (Michael Shannon), his dead father's arch-foe, and his cohorts threatening to destroy the Earth.
Adams, gathered with the film's cast for a press conference before its June 14 US release, noted that the actors actually finished shooting it two years ago, after which the Computer Generated Imagery (CGI) artists got to work.
It is the second CGI-powered superhero blockbuster of the summer so far, after Marvel's "Iron Man 3", and amid talk of a sequel to last year's "The Avengers", the third highest-grossing film in box office history.
The pre-release industry buzz for "Man of Steel" has been very positive, fueling inevitable speculation about possible follow-ups.
Cavill, for whom the role is arguably the biggest of his career so far, admitted he would be happy if there were. Indeed the contract he signed gives the film's makers options on using him for two further movies.
"There's nothing planned just yet that I'm aware of .. but time will tell," he said, before adding: "As far as, if there is one, would I like it? Yeh, I'd like it very much.
"I think it would be a lot of fun to continue telling this story," he said.