Former Prime Minister of Portugal Antonio Guterres is set to be sworn in as the next United Nations Secretary-General today.

Guterres, 67, was the Prime Minister of Portugal from 1995 to 2002, and the UN High Commissioner for Refugees from June 2005 to December 2015.

He will become the world's top diplomat on 1 January 2017, and hold that post for the next five years.

He was formally appointed by the General Assembly on October 13 in what was the culmination of a historic process member states set in motion late last year: the selection of a new United Nations Secretary-General, traditionally decided behind closed-doors by a few powerful countries, for the first time in history, involved public discussions with each candidate campaigning for the Organization's ninth chief.

These so-called 'informal briefings' between the candidates, UN member states and civil society representatives kicked off on 12 April, when the first three candidates presented their 'vision statements' and answered questions on how they would promote sustainable development, improve efforts to create peace, protect human rights, and deal with huge humanitarian catastrophes should they be selected to lead the Organization.