The Windsor Framework has been formally signed off at a meeting in London between UK and EU officials.
British Foreign Secretary James Cleverly and the European Commission's Maroš Šefčovič chaired a meeting to formally adopt the new arrangements for Northern Ireland, after the Government won the backing of MPs for the Windsor Framework earlier this week.
The vote by MPs in favour of regulations to implement the Stormont brake, a key part of the Windsor agreement, came despite former UK prime ministers Boris Johnson and Liz Truss joining the Democratic Unionist Party and hardline Brexit-backing Tory MPs in voting against the deal.
The formal sign-off, which is understood to have happened mid-morning, comes as Jeffrey Donaldson's party continues to oppose the deal brokered by the Government, with no sign of the DUP yet being willing to return to powersharing.
The formal sign-off happened at a meeting of the Withdrawal Agreement Joint Committee, with the UK Foreign Secretary and Mr Šefčovič also due to attend a meeting of the Partnership Council - another of the implementation bodies under the Brexit deal.
"By formally approving the Windsor Framework, we are delivering on our commitment to provide stability and certainty for Northern Ireland," Mr Cleverly said ahead of the meeting.
"The framework is the best deal for Northern Ireland, safeguarding its place in the Union and protecting the Belfast (Good Friday) Agreement.
"I look forward to further effective co-operation with the EU on key issues, such as security and energy."
The UK hopes that the new deal on the protocol can mark a step towards British participation in the EU's €100 billion Horizon programme, with science and research likely to feature in official discussions between the pair.
Mr Cleverly and Mr Šefčovič will also discuss a recent agreement between the UK, Ireland and the EU on Peace Plus, the cross-border peace funding programme.
The continuing stand-off at Stormont suggests the prospects for a return to powersharing in time for the 25th anniversary next month of the Good Friday Agreement remain bleak.
The executive and the Assembly have been suspended since the DUP walked out last year in protest at the way the Northern Ireland Protocol negotiated by Mr Johnson was operating.