British actor Nicholas Hoult knew he was shooting a big-budget fairy tale — with all the melodrama such an undertaking entails — but he couldn’t help tweaking his “Jack the Giant Slayer” director, Bryan Singer, about the storyline.
“I’d wind him up about some of the cheesier aspects of it,” Hoult tells The Post, “say things I shouldn’t say.”
Singer, however, was into it.
“This is a movie where you want some nods and winks, you don’t want to take it too seriously,” says Singer. “That way, you can get away with more action. As long as you make it fun. And Nicholas would just make jokes, come up with the NC-17 version of Jack. A lot of dark humor.”
You’d be hard-pressed to match this clever, hunky 23-year-old with the awkward, bowl-cutted preteen we first met in 2002’s “About a Boy,” singing “Killing Me Softly” a cappella, to mass audience cringes.
In “Giant Slayer,” out now, Hoult plays the titular Jack, who ends up scaling a miles-high beanstalk to rescue a plucky princess and dispatch some enormous bad guys in the process.
A reimagining of “Jack and the Beanstalk” and an earlier, darker Cornish tale called “Jack the Giant Killer,” it also features Stanley Tucci as a very “Princess Bride”-esque royal villain, Ewan McGregor as a valiant right-hand man to Ian McShane’s king and Bill Nighy as the voice of the two-headed ruler of the giants.
The big-budget action flick comes on the heels of another fantasy/sci-fi role for Hoult, as the emo zombie reanimated by love in last month’s “Warm Bodies,” and precedes two more major parts next year, in “Mad Max: Fury Road” and “X-Men: Days of Future Past.”
What’s made Hoult rise through the ranks as one of the most sought-after young men in movies? “He’s got a lot of charisma, and a lot of acting chops,” says director Singer, who’ll also be helming “X-Men” (and produced or directed the first two installments, as well as last year’s “X-Men: First Class”).
“But he also has this very vulnerable side to him, as well as a wicked sense of humor,” Singer says. “You want all those aspects in a central character.”
Here’s who else wanted all those aspects, until recently: Oscar winner Jennifer Lawrence, who dated Hoult — her “X-Men: First Class” co-star in 2011 — for two years until the couple’s breakup just last month. Shortly thereafter, he was spotted on a date with an Italian actress named Tatiana Luter.
His sharp-cheekboned good looks have also earned him roles like Tony Stonem, the teen ladies’ man in the first two seasons of the 2007 UK show “Skins” (MTV put out a pale and short-lived imitation two years ago) and as a much-younger love interest of Colin Firth’s character in the 2009 Tom Ford-directed movie “A Single Man.”
As transitions from child to adult actor go, Hoult seems to have fared much better, genetic-ally, than most. It’s not uncommon to see a once-adorable young sprite from a favorite TV show or movie show up at 16 looking . . . all wrong, somehow.
But the growing-up years, says Hoult, were still awkward in their way, and they were when he learned to keep everything in perspective. Though he did appear in various TV and films after his big debut at 12 in “About a Boy,” nothing approached the same level of mass exposure until “Skins” — and that might have been just as well.
“Yeah, I stayed in school and would audition for things, and not always get them,” he says. “There’s this difficult phase, because you’re not right for a lot of things — you’re too young or too old. Not a lot of opportunities. But I was able to have a normal life. I didn’t focus too much on the acting and didn’t get overwhelmed by it all.”
Hoult, the son of a pilot and a piano teacher, was raised in a small town called Reading and attended the Sylvia Young theater school in London, but also honed his craft as a choirboy and a trombone player.
Nowhere in his school days were equestrian skills on the bill, which is why shooting his “Jack the Giant Slayer” stunts presented a bit of a new challenge.
“I’d been on a horse before,” he allows, “but I certainly have no control over them. We had a relationship where I asked the horse to do things, and it ignored me. I didn’t feel confident bullying them into submission. That was totally unsuccessful.”
Fortunately, he won’t have to cringe-watch his own horseback riding on the big screen, as he tends to avoid watching the finished product.
“I don’t really watch [my movies], to be honest,” he says. “I guess I will one day, when I’m sitting at home in my rocking chair.”
sstewart@nypost.com