Halle Berry, 33, has a strange effect on others, her “Bullworth” costar and director Warren Beatty, 64, told the New York Times Magazine: “When people walk into a room and see Halle,” said Beatty, “they always laugh. They don’t know how else to react. They’re not used to seeing someone that beautiful.” Now set to open in the new film “Monster’s Ball,” for which the National Board of Review has just named her the best actress of 2001, Berry has a few things to say about herself, too — as well as about her costar, Billy Bob Thornton. The film reportedly has a sex scene so graphic that a minute had to be cut from it to avoid an NC-17 rating. “I would only do it if Billy Bob agreed to be as naked as I was,” she told The Times, noting that in “Swordfish,” her breasts made their wide-screen debut. “The producer (of ‘Swordfish’) told the press this lie that I got more money for the part — $250,000 for each breast. Well, if I were charging for them, it would be a lot more than $500,000.” Still, she concedes, the nudity in that film, which she termed “gratuitous,” gave her the courage to do the sex scene in “Monster’s Ball,” a dark drama about racism and capital punishment. “We shot the sex scene on Day 19 of a 21-day shoot,” she said. “I always say Billy Bob and I dated for three weeks, and then we had sex.” Admitting that the scene “scared me completely,” Berry went on to say, “I look at it now and think, ‘Who is that girl up there?’ ” The movie opens Wednesday in New York and Los Angeles.