The development came after a night of intensive talks between Northern Ireland Secretary Brandon Lewis and DUP and Sinn Féin delegations in Belfast.
So, why has Edwin Poots resigned from the DUP - and who might replace him?
Former DUP leader Arlene Foster's resignation as first minister on Monday set a seven-day clock running within which her successor, Lagan Valley MLA Mr Givan, must be appointed.
So far, Givan is now is expected to be sworn into office as the new first minister, with Sinn Fein's Michelle O'Neill as deputy first minister.
Earlier today, Mr Poots had nominated Paul Givan for the role of First Minister despite opposition from a large number of senior people within the party.
The announcement by Mr Poots, who now remains Northern Ireland Agriculture Minister, concluded a hugely turbulent 24 hours in Northern Ireland politics - a period in which power-sharing appeared to have dodged another crisis following the nomination of First and Deputy First Ministers in a special Assembly sitting, only for the administration to be plunged back into uncertainty hours later with Mr Poots' departure.
"Whoever leads the DUP is a matter for that party".
"The DUP is remaining very tight-lipped in terms of their approach to the First Minister, and, of course, electing a new leader - whether that will be by contest, or whether they'll rally behind one name now, is hard to know", he added.
Sinn Fein will therefore participate fully in the five-party executive, McDonald said in a statement, clearing the way for Givan to become first minister.
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"The Government will work with all parties and the British Government to protect the institutions of the Good Friday Agreement and work to ensure the continuation of the Assembly and the Executive".
"We have monumental challenges ahead that will require unity of objective and urgency".
"We will do everything we possibly can in a constructive way to facilitate a stable outcome here".
Explained: What went wrong for Edwin Poots, the DU.
UK, Australia agree post-Brexit free trade deal
And, the FTA also means that Brits under the age of 35 will be able to travel and work in Australia more freely and vice versa. The country is home to eight of the 10 biggest farms in the world - including one which is larger than Israel.