Heath Ledger, the intense young Australian actor, is best known in America for his roles as a rebellious high school hunk in “10 Things I Hate About You” (1999) and as Mel Gibson’s committed son in “The Patriot” (2000), but he made his first mark in the U.S. in the short-lived 1997 Fox Network series “Roar,” in which he played a Celtic prince leading resistance to Roman oppression in fifth-century Britain. Now he’s returned to the medieval milieu as the star of one of the summer of 2001’s first major pictures, Brian Helgeland’s “A Knight’s Tale,” a Columbia release opening on May 11 which lightheartedly portrays fourteenth-century jousting as the equivalent of such contemporary sports extravaganzas as football or wrestling. Ledger plays William Thatcher, a youth of low birth who’s served for years as an attendant to a nobleman who’s plied the jousting trade. When his master dies, William persuades his pals Roland (Mark Addy) and Wat (Alan Tudyk) to help him impersonate a knight so that he can join the jousting circuit–a dream he’s nurtured since childhood. His success attracts not only a bitter rival in the wicked Count Adhemar (Rufus Sewell), but the attentions of a lovely damsel named Jocelyn (Shannyn Sossamon), as well as the respect of the disguised Prince Edward of England (James Purefoy). Will William get the girl, survive possible unmasking as a fraud, win the championship and make his elderly father proud? And will audiences embrace a medieval action film/romantic comedy which plays with anachronism by using a rock score and having fourteenth-century spectators sing “We Will Rock You” and do the “wave,” as well as inserting the young Geoffrey Chaucer into the mix as Thatcher’s spokesman and announcer?

If the crowd’s reaction at a recent Dallas screening is any indication, the answer to the latter question will be a resounding yes. The screening was in connection with a visit by Ledger to promote the film. Though he was clearly tired–having worked, as he explained, virtually eighteen months straight on “The Patriot,” “Tale,” and the recently-completed remake of “Four Feathers” and preparing for a nice, long rest before undertaking another role–he warmed to questions about acting. “Shooting a film is what I love,” he said with enthusiasm. “I really get off on that time between ‘Action’ and ‘Cut.’ It is hard work. That is the fun. It’s a medium of expression. There’s a fine line between this profession and being a shrink. You really have to observe and understand people. You have to observe and understand yourself. And it goes beyond exploration of characters and people–it has a lot to do with self-exploration, and getting to know yourself before you can portray someone else. It’s very interesting that way. And beyond that, you just get to live all these emotions and times and stories.” He added with a smile: “And you play with swords and ride horses with a big stick. It’s called a lance.” Ledger likened acting to interpreting notes of music on a page, sometimes emphasizing one aspect of a character and then another: “You can never become the character. Ultimately it’s you up there. You’re just drawing upon things that you’ve experienced and heightening different emotions. You’ve got to get in there and understand yourself as an instrument to be able to do that.”

When Ledger first got the script of “A Knight’s Tale” to read, he was almost turned off by the initial appearance of “We Will Rock You” as the anthem played at the beginning of the jousting tournaments. “I almost closed the script,” he recalled, laughing. But then he reconsidered and came to appreciate the writer-director’s approach: “It’s gutsy, and it’s smart, too, because presenting the movie with this rock-and-roll music, it really just presented a sledgehammer that bashed down any walls or barriers that were restricting us to historical correctness. And it’s not a movie about that–it’s not a BBC biopic on a young knight. It’s a fairy-tale. It’s not pretending to be anything but that.”

Ledger said that the role of William Thatcher was a physically demanding one, though. One challenging aspect was doing the tournament scenes on horseback: “They actually got in a professional jouster, from Vegas” to help him and the stuntmen train. “He jousts, believe it or not, at the Excalibur Hotel.” And the armor was distinctly uncomfortable: “It’s metal, and there’s a lot of it, and it weighs you down. It’s sweaty, it’s itchy. And you can’t sit down because you can’t fit in any chair, so you’re constantly sitting on apple boxes.”

Ledger grew up in Perth and did a good deal of Australian television before landing the role in “Roar” (which shot Down Under). Since his film career exploded, he’s noticed a distinct upswing in public recognition on his periodic returns home. “Things change in leaps and bounds in terms of that,” he admitted. “This [last] time, it had really, really changed, and it was quite scary. It was very invading, and I was very self-conscious. It’s in that strange transitional stage now where it’s life-changing. Anything that big, that could possibly change the rest of your life, is a little strange and a little surreal, and you just have to start figuring it out for yourself.”

But he’s learned not to take his newly-minted star status too seriously. Asked how “A Knight’s Tale” might affect him, he mused, “It all depends on that first weekend [of grosses]. After that I’m sure that if it’s a success there’ll be little [action] figures and stuff like that. I’d laugh [if that happened]. And I have friends around me that [would kid me so] that I’d never live it down.” He pointed to a poster for the film, which featured his grim face accompanied by the words “He Will Rock You.” “That ‘He Will Rock You’ line,” Ledger laughed. “You don’t know how many messages I got on my phone, my mates just giving me so much hassle on that–[saying] ‘You rock me, man!'”

And then Heath Ledger flashed the smile that’s helped make him one of the screen’s hottest young actors.