Gwyneth Paltrow, girlfriend of Brad Pitt, wants to stop the tresses. ''I'm sick of all the hoopla about Brad's hair,'' says Paltrow, who will costar with Morgan Freeman and the newly shorn Pitt in the psychological thriller Seven, out in September. ''I swear, if I hear one more time, 'What happened to his hair?' I'm going to scream.'' Passions have been running high since Pitt decided to lop off his Legends of the Fall mane. In fact, according to Paltrow, one interviewer was crushed when she revealed Pitt had gotten a buzz cut. ''Don't people have anything else to worry about?'' she asks. And while she's setting the record straight, there's the little matter of Pitt's ''Sexiest Man Alive'' title. ''Everyone is making all this fuss over Brad,'' says the actress, ''but I'm telling you, Morgan Freeman is the sexiest man alive. You heard it here.'' Okay, but who tells Brad?