AS a comedy actor Alfred Marks has enjoyed a lifetime of laughs. But ask him what's the funniest experience he's ever had and he barely needs time to reflect. ''Getting married'', he shoots back. As the Keeping Posted eyebrows rose questioningly, Marks explains: ''My wife and I were both appearing in a play in the English seaside town of Margate the day we got married. But my wife was overcome by nerves and not able to go on stage. So I had to wear a dress, fishnet stockings and a wig and go on and play her role as well as mine. So on my wedding night I was actually a transvestite.'' Despite that rather dubious start, the 42-year marriage of Marks and his comedienne wife Paddie O'Neill is one of the enduring tales of British showbiz. Paddie quipped: ''Apart from Mickey and Minnie Mouse, ours is probably the only marriage in show business to last so long.'' Marks, a much-loved and versatile veteran of stage and TV screen is here for the Hilton Playhouse production of Lend Me a Tenor which opens tonight and runs until November 27. He describes the play (which also stars Nyree Dawn Porter of The Forsyte Saga fame) as ''sophisticated comedy, not a drop-your-trousers farce''. The production is on a 12-week swing through the Middle East and other parts of Asia and is here on the penultimate leg. And Marks' wife Paddie has gone along for the trip. Paddie said: ''I'm just backstage doing nothing - which is my favourite role. Alfred and I hardly ever work together, which is probably why we've stayed married for so long.'' Then, looking fondly at her husband, Paddie said: ''Alfred brought me along on this trip because he couldn't bear to leave me alone at home.'' Growled back Marks in response: ''I brought you with me because I don't trust you alone at home.'' Domestic blitz, indeed!