The Countess is stepping out of her role as a reality star on the “Real Housewives of New York City” and leaving behind her clothes for an appearance on “Law & Order: SVU.” LuAnn de Lesseps will play an eccentric art patron who poses semi-nude for a painter. De Lesseps begins shooting tomorrow for three days at Chelsea Piers. The episode, to air Feb. 23, opens with a crime scene involving her character. De Lesseps is the first ‘Housewife’ of the Bravo series to land an acting gig, although some may argue the entire “reality” show is badly acted.