The African Union (AU) is a continental union consisting of all 55 countries on the African continent, extending slightly into Asia via the Sinai Peninsula in Egypt. It was established on 26 May 2001 in Addis Ababa, Ethiopia, and launched on 9 July 2002 in South Africa, with the aim of replacing the Organisation of African Unity (OAU) established on 25 May 1963 in Addis Ababa, with 32 signatory governments. The most important decisions of the AU are made by the Assembly of the African Union, a semi-annual meeting of the heads of state and government of its member states. The AU's secretariat, the African Union Commission, is based in Addis Ababa.

Is it true that is south africa part of the african union?
yes