Al-Tuwaijri, who studied aeronautics and business, was a Saudi Air Force pilot before working for a number of banks. He became minister of economy and state planning from 2017 until he was relieved of his post in March. He has also been on the board of directors at Saudi Aramco, Saudi Railways and Saudi Arabian Airlines and says his private sector experience allows him to take a "fresh look" at the WTO.
Some delegates say political tensions with Qatar might prevent him earning broader support.
A former doctor and defence minister, Fox campaigned for Britain to leave the European Union and, after the Brexit vote, became secretary of state for international trade, but lost his position a year ago.
Fox, who was given early odds of 33/1 by betting agency Ladbrokes before the vetting process began, says this is a job for a politician "and probably one who has been around for a while and carries the scars of the most difficult battles."
