The president's post is a ceremonial one in Ethiopia.
The prime minister's chief of staff, Fitsum Arega, said the new president will bring "the right competence" and "experience to the office".
Zewde, who is a well-regarded diplomat representing Ethiopia at global, continental and regional organisations including the United Nations and the Intergovernmental Authority on Development, had also served as Ethiopia's ambassador to various countries. Sahle-Work, as her name denotes, has been described as an experienced diplomat who recently held an office with the UN.
Sahle-Work's appointment comes just a week after Prime Minister Abiy Ahmed overhauled the Cabinet. "Therefore, we need to work on peace for the sake of our mothers", Zewde told parliament after her approval.
The two houses of the Ethiopian parliament would convene their second special meeting on Thursday to decide on the resignation submitted by President Mulatu Teshome Wirtu.
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Ethiopian lawmakers last week approved a Cabinet with women making up a record 50 per cent of ministers, including the country's first female defence minister. "By her being the president, we feel like now the 50 percent of us is represented in that". Zewde is a resounding demonstration of the changing fortunes for the indefatigable and distinguished women of Africa.
The prime minister, who is the head of state, holds executive power.
The Horn of Africa power joined a handful of countries, mostly European, where women make up 50 per cent or more of ministerial positions, according to the Inter-Parliamentary Union and U.N. Women.
4 - Other global positions she has previously held include: - Special Representative and Head of the United Nations Integrated Peacebuilding Office in the Central African Republic (BINUCA) - Permanent Representative of Ethiopia to the African Union and the United Nations Economic Commission for Africa (ECA) - At home, Director-General for African Affairs in the Ministry of Foreign Affairs.