WHEN DAISY MILLER came out last Summer, there was some question whether Cybill Shepherd had magnificently captured the dull vapid chattering character of Daisy, of whether she was just a bad actress. Peter Bogdanovich has evidently decided to set the record straight for in his new movie At Long Last Love, he gives ample evidence that Shepherd is a very bad actress in deed.

This isn't to say that Shepherd ruins At Long Last Love. The movie would be quite bad enough without her But her clodhopper dancing and mynah bird singing contribute substantially to the downfall of the film. Her co-star, Burt Reynolds, is just as bad--he whispers rather than sings and his dancing is so inept that Bogdanovich has cropped his body at the knee most of the time. The rest of the cast--Bogdanovich standbys like Madeline Kahn and Mildred Natwick--do better, and Eileen Brennan is even good. It's a pity she didn't get top billing.

The movie is basically another Bogdanovich nostalgia trip--this time to the world of the 1930's movie musical, with songs by Cole Porter. Since At Long Last Love has been universally panned, and the theaters it shows at are generally empty, the suckers sitting in the audience can lessen the pain somewhat by singing along with "You're the Top." "Lot's Misbehave" and other Porter masterpieces. The plot is a typical romantic quadrangle between Shepherd, 'Reynolds, Kahn and a stereotyped greasy Italian gambler played by Diullio del Prete. They cavort between two hotel rooms, one mansion, several parks, two formal dances, one race course, a plethora of white Rolls Royces and the Lord and Taylor Ladies Room. Eventually everyone ends up with the right mate and lives happily ever after. The genre is basically Fred Astaire Ginger Rogers, with a few trademarks of Gene Kelly and Katharine Hepburn thrown in.

But Bogdanovich hasn't captured the style that made Astaire and Rogers so special. He user the overblown sets and casts of thousands that helped to kill of movie musicals in the late 60's when Fred and Ginger started dancing, all the people and furniture disappeared. Cybill and Burt, on the other hand, come dangerously close to bashing into a number of white silk couches--and also the other dancers.

The one thing that held together the stupid plots of 1930's musicals was the sharp, witty give-and-take between characters--Aline MacMahon fighting with Guy Kibbee, for example. But the pace is so slow in Bogdanovich's film--most of the time the actors shout to each other from across a room--that the little wit he put into the script gets swallowed up by the chandeliers. And Astaire needed the foil of stupid, stuffy Edward Everett Horton to show off his own urbanity. Reynold's counterpart to Horton is his mother, normally silly Mildred Natwick, who breezes in and out in two scenes with exceptional sanity, leaving Reynolds only his own acting ability to prove his sophistication. Unfortunately, that's not enough. Eileen Brennan as a crass, nymphomaniacal maid is a welcome counterpart to Shepherd. But Cybill still insists on gimmicks like crescendoing off-key "Or is it at long last love?" and then sticking her tongue into her cheek, shrugging her shoulders and giggling.

The problem is tha Bogdanovich has overblown the whole thing. The scale he uses is far too large, the little that is clever in the script or acting gets swamped, and the acting, singing and dancing aren't good enough to even begin to make up for it.

There is a slim chance, however, that the movie will not be a total waste. Rumor has it that Shepherd and Reynolds became what Modern Screen Magazine refers to as a "Woosome twosome" during the filming. If this is true we may just possibly be spared any more attempts by Bogdanovich to turn his girl friend into a star. For the guarantee of no more Cybill Shepherd movies, I would be willing to sit through anything.