Famed composer Cole Porter's life has been film fodder before. But in 1946's ''Night and Day,'' Cary Grant played him as a straight romantic lead instead of the gay man he actually was. In Kevin Kline's portrayal, Porter's real sexual exploits -- as well as his platonic marriage to socialite Linda Lee Porter (Ashley Judd) -- are more honestly explored, backed by dreamy musical performances from the likes of Elvis Costello (''Let's Misbehave''), Sheryl Crow (''Begin the Beguine''), and Alanis Morissette (''Let's Do It [Let's Fall in Love]''). ''I like the way it scrambles the whole movie-musical convention. There's something sui generis about it,'' says Kline, who tackles several numbers himself, even though Porter wasn't known as the best crooner. ''I didn't think about singing it as a singer; the point was to sing it as the composer,'' he says. ''The Broadway composers I've been privileged to hear singing their own music, it's not a pretty picture.'' Though he worked to experience Porter's intense emotional highs and lows, Kline says he was able to leave them on the film's London set. ''What I'd take home is the songs,'' notes the actor. ''Sometimes I'd go back to the hotel and play some Mozart just to get them out of my head.''
THE GOOD NEWS Pop stars singing Porter.
THE BAD NEWS ''Chicago'' notwithstanding, musicals are a tough sell, even tougher in the summer.