On 2 December 1965, Smith wrote a personal letter to the Queen asking her to accept Dupont as Governor-General of Rhodesia. In response, the Queen replied, "Her Majesty is not able to entertain purported advice of this kind, and has therefore been pleased to direct that no action shall be taken upon it". Smith was attempting to assert his claimed prerogatives as Her Majesty's Rhodesian Prime Minister. However, the UK, with the near-unanimous support of the international community, maintained that Gibbs was the Queen's only legitimate representative in what it still considered to be the colony of Southern Rhodesia, and hence the only lawful authority in the area. Under the 1965 Constitution, if the Queen did not appoint a Governor-General within fourteen days of advice being tendered by the Prime Minister, a Regent was to be appointed. In deference to the Royal Family, however, on 16 December, Smith amended his original plan and Dupont was appointed as Officer Administering the Government. He would continue to use the title until the declaration of a republic in 1970. In a referendum held on 24 June 1969, the predominantly white electorate approved a new constitution making Rhodesia a republic, with the President as ceremonial head of state. A Bill to that effect was passed by the Legislative Assembly on 17 November, and was signed into law by Dupont on 27 November. Dupont's last duty as Officer Administrating the Government was to sign the proclamation of a republic on 2 March 1970. Following the declaration of a republic on 2 March 1970, Dupont was made interim President pending the elections under a new constitution on 10 April. When Rhodesia was formally declared a republic, Parliament elected Dupont as President on 14 April. During the latter period of his term he suffered long bouts of ill health, and retired on 31 December 1975. Dupont initially married in London in 1933 to Barbara (Barbie). They divorced in 1942. He and Barbie had two children; Hilary and Graham. Graham died in childhood in England in 1942. In 1946, he married his second wife Betty 'Timmy' Wood at Kensington Registry Office. Wood was fifteen years his junior. In 1947, they had a son, Stephen. Betty 'Timmy' died in 1957 in Salisbury, and was buried in Warren Hills. His two children, Hilary and Stephen, were killed in 1958, when their Central African Airways plane crashed near Benghazi. On 23 May 1963, he married Armenell Mary Betty Bennet, originally from Cornwall, who was a branch organiser for the Rhodesian Front.