Robert Mugabe has agreed to stand down as Zimbabwean President following a military takeover earlier this week.
A source close to the ailing leader said he was reportedly working on his resignation statement ahead of a live address to the nation which is due to be televised later this evening.
The ZBC state broadcaster confirmed that Mr Mugabe would address the nation shortly from his official State House office in the capital Harare.
The 93-year-old had previously refused to step down despite being under house arrest since Wednesday after the military launched a takeover.
Earlier on Sunday the ruling party, Zanu-PF, held a meeting of its central committee where they removed him as the head of the party and warned that he must resign or face impeachment.
Mr Mugabe, who has ruled Zimbabwe since the end of white-minority rule in 1980, was reportedly trying desperately to cling onto power and was believed to be in talks with the head of the armed forces, General Constantino Chiwenga, to negotiate the terms of his resignation.
It is unclear what deal he has agreed and whether this will include protection from prosecution for him or his wife, Grace.
The Mugabes said Mr Mnangagwa, who fled to South Africa but has since returned, had shown "traits of disloyalty, disrepect, deceitfulness and unreliability" but some have said it was a ploy to make way for Grace to succeed her husband as president.
Ms Mugabe is widely reviled as "Gucci Grace" within the country for her extensive shopping habits. She has been compared unfavourably with Mr Mugabe's first wife, Sally Mugabe, who died in 1992 and is regarded as the "Mother of the nation" by most ordinary Zimbabweans.
As a result, during the early years of her tenure as First Lady she largely tried to keep out of the political spotlight and instead focused on charity work.
But in 2014 the couple began to think about the succession and to clear a path for her to succeed him.
Mr Mugabe appointed her as head of Zanu-PF's Women's League which gave her a key seat on the party's ruling Politburo and set up Youth League to support her.
During the 2000, the Mugabe regime began to systematically strip white farmers of their land and give it to people loyal to the party.
This meant agricultural product collapsed in a country which was once known as the "bread basket of Africa" which led to a major economic crisis and hyperinflation.
During hyperinflation's peak between 2007-8, there were 35 quadrillion Zimbabwean dollars to one US dollar.
After the country abandoned the currency in face of US dollars the situation stabilised somewhat but the latest estimate of GDP per capita is just $2,276 (£1723) per person.
Additional reporting by agencies
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