Burton will play a powerful executive whose business partner is murdered. Fleming will make a voice-over cameo as the mother of a suspect, who is an opera singer. De Lesseps will play a socialite who makes a shocking discovery.
Recently seen in the Lincoln Center Theater production of The Grand Manner, Burton has been Tony-nominated for her performances in The Constant Wife, The Elephant Man and Hedda Gabler. Other stage appearances include Spring Awakening, The Water's Edge, The Beauty Queen of Leenane, An American Daughter, Company, Some Americans Abroad, Alice in Wonderland and Present Laughter.
"Law & Order: Special Victims Unit" airs Wednesdays at 10 PM ET on NBC.