Natty and smart is the public persona of WJMD-FM's popular Johnny Holiday. Beefy and bungling is the image Buddy Piccolino has earned in his rewarding years with Harlequin Dinner Theater. Now they are together on that Gaithersburg stage in Neil Simon's clever comedy, "The Odd Couple," about why two marriages failed.

But, contrary to what you might expect, Holiday is playing the sloppy one, Oscar, and Piccolino is appearing as the natty one, Felix. What may be an interesting challenge for performers - to play against their own image - can become an irritating challenge for their audiences, to accept the purposeful switch.

In the case of these two reversals, director Nicholas Howay has been too clever for the play's and the players' own good. When Walter Matthau and Art Carney premiered the comedy here at the National under Mike Nichols' direction they were acting within their persona, as were Jack Klugman and Tony Randall in the TV series which lasted for years. No matter how novel and idea may seem, audience expectations must not be scorned.

Thus, while "The Odd Couple" still works as a brilliantly conceived comedy which essentially is a serious study in the mismatchings of spouses, it must chug uphill under Howay's faintly scornful approach. There is a pushing and heaving for effects Simon's script amply allows. This is illustrated again in the forced efforts of Leigh Anne Duncan and, to a far lesser degree, of Michele Sommer, as the Pigeon sisters, those chirpy English birds whom Simon used to reflect the mid-'60s chic of British secretarial voices.

The poker-playing buddies who come to the Riverside Drive apartment shared by the divorcing husbands remain amusing, but "The Odd Couple" can work far more effort-lessly than Harlequin presents it.