Joining a roster of celebrities that over the years has included Muhammad Ali, Michael Douglas and the late Audrey Hepburn, "Girl, Interrupted" Oscar winner Angelina Jolie is to be appointed a United Nations goodwill ambassador during an event at the agency's Geneva headquarters on Monday. Kris Janowski, spokesman for the U.N. High Commissioner for Refugees, said Jolie, 26, "is the kind of person who can get our message across to young people." In her recent action film "Lara Croft: Tomb Raider," Jolie was shown amid scenes shot in Cambodia at Angkor Wat, the largest religious monument in the world and the best known of the scores of old Buddhist and Hindu temples around Cambodia. Last month, reports the Associated Press, the actress visited Cambodia as a guest of the UNHCR, which works with displaced people and refugees. She also has visited work sites in Africa. In her domestic life, PEOPLE reported in June, Jolie carries drops of husband Billy Bob Thornton's blood in a pendant around her neck. The couple also used their blood to sign wills they rewrote earlier this year. And, as a first wedding-anniversary present, Jolie, gave Thornton, 45, his-and-her grave plots in Louisiana.