Speaking of which: who on earth is Matthew McConaughey? (Say Mc-con-a-hay.) He’s the star of the upcoming John Grisham adaptation of ““A Time to Kill.’’ He’s the subject of a buzz to end all buzzing. And he may be God’s gift to Hollywood. The movie industry has more grunge actors than it needs. But it has few young men cut from classic, leading-man cloth, and even fewer young bucks who are bankable: Tom Cruise, Brad Pitt, Keanu Reeves on a very good day. Executives everywhere sat bolt upright when Warner Bros. tapped an unknown to carry a $40 million picture. (Sandra Bullock has a supporting role.) Rival studios were itching to sign McConaughey when they’d seen only the ““Kill’’ trailer. But Warners has a three-movie contract with the actor and has declined to let him go make money for anybody else.

McConaughey was paid $200,000 for ““Kill.’’ Sources predict he’ll be worth $4 million a movie after it opens on July 24. He’s already been cast opposite Jodie Foster in ““Contact,’’ a sci-fi thriller based on a Carl Sagan book. He’s been photographed for the cover of Vanity Fair and even been granted an audience with Paul Newman, who is his hero and the reason he named his dog Ms. Hud. The whirlwind is worrying. Not because McConaughey’s untalented – in ““Kill,’’ he does a sexy, kinetic turn as a young Mississippi lawyer defending a poor black man (Samuel L. Jackson) in a murder trial – but because he’s a nice guy. ““He is, isn’t he,’’ says Warners president Lorenzo Di Bonaventura. ““Let’s hope Hollywood doesn’t kill him. I don’t think there’s anything you can do to prepare yourself for the onslaught that happens when you hit like he’s going to hit.''

In person, the actor is funny and open. He will show you his journal. He will show you his muscles. He will also rave about ““The Greatest Salesman in the World,’’ a motivational book he re-reads endlessly. Go ahead, roll your eyes. But consider how he landed the ““Kill’’ lead: he asked for it. McConaughey was originally cast in a minor role. One day, he asked director Joel Schumacher if Brad Pitt was playing the lead. ““No, he’s not,’’ said Schumacher. ““Do you think he should?’’ McConaughey, whose biggest role had been in ““Return of the Texas Chainsaw Massacre,’’ looked him in the eye: ““No, I think I should.''

The great salesman was born in Uvalde, Texas, and grew up in Longview, east of Dallas. Pop owned a pipeyard during the oil boom; Mom was a substitute teacher. McConaughey and his brothers, Pat and Rooster, could watch one hour of TV a day. ““The rule kind of was: if it’s daylight, you’re outside,’’ he says. ““We ran around in cut-offs, building tree houses, crawdad-hunting and frog-gigging.’’ (How do you gig a frog? ““You take a three-pronged spear…’’ OK, never mind.) By 1992, McConaughey was studying film at the University of Texas in Austin and beginning to direct shorts. One night, he met a casting director in a bar. They bonded so loudly, they got kicked out. McConaughey, who’d never acted, was cast in ““Dazed and Confused,’’ as a hilariously skanky stoner who preys on high-school girls. He finished college, then played the killer in ““Chainsaw.’’ ““It was a hoot, man,’’ says McConaughey. ““I got a mechanical leg, and I was driving a tow truck and running people over.’’ He also played the adorably square cop who falls for Drew Barrymore in ““Boys on the Side.''

Meanwhile, Schumacher and Grisham had been involved in a tortured, yearlong search for a leading man, vetoing Kevin Costner, Keanu Reeves, Val Kilmer and Woody Harrelson. ““Every name in the world was mentioned for this role,’’ says Schumacher. ““You’d think we were casting Scarlett O’Hara.’’ The director had had his eye on McConaughey, and invited him to do a screen test. Says Schumacher, ““When we started doing a scene, the makeup woman and the hair guy – everybody started tiptoeing around in the dark saying, “Who is this guy? He’s fabulous.’ The cameraman just loved lighting him.’’ McConaughey was making John Sayles’s ““Lone Star’’ when he got a conference call from Schumacher and Grisham: ““They said, “Let’s make a movie.’ I went to the set photographer and said, “Alan, can you take some pictures of me right now? I think I’m glowing’.''

McConaughey is still glowing: from the money, from the prospect of fame. Paul Newman advised him to take his work seriously, but not himself. To keep his word. And to give ’em hell. Will Hollywood give McConaughey hell? Schumacher believes he’ll be fine because he’s a true talent and comes from a solid family. But does McConaughey really want to be a celebrity, to have helicopters at his wedding, to have tabloid reporters tracking his family down?

This last item stops the actor short: his father died in 1992, and his mother is so kindly she trusts everyone. McConaughey admits he hasn’t thought all the privacy issues through. ““I’ve seen people get cynical in this business,’’ he says. ““I know I’ve got to work my butt off to maintain a good perspective. I don’t think I can be alive unless I’m looking at the world as a good place.’’ The phone rings. It’s the paparazzi. McConaughey’s actually going to tell them when he’s leaving the building. ““I will be heading out at about 5,’’ he says, brightly. ““Will that work? Right on. Thank you.’’ Well, good for him. He’s learning. He lied.