US President Donald Trump has announced that his acting Chief of Staff Mick Mulvaney is to become the US Special Envoy to Northern Ireland.
The role has been vacant since Mr Trump took office.
Mr Mulvaney is an Irish-American with family roots in Co Mayo.
He has been the acting White House Chief of Staff since December 2018 and will be replaced in the role by Republican Congressman Mark Meadows.
In October, in the midst of the impeachment proceedings against Mr Trump, Mr Mulvaney was criticised for his admission during a press conference that the president had tied military aid for Ukraine to Kiev opening a probe into the Democrats.
"We do that all the time with foreign policy," Mr Mulvaney told reporters. "Get over it. There is going to be political influence in foreign policy."
He walked back that admission only hours later.
The Irish Embassy in Washington has welcomed Mr Mulvaney's appointment.
....I want to thank Acting Chief Mick Mulvaney for having served the Administration so well. He will become the United States Special Envoy for Northern Ireland. Thank you!— Donald J. Trump (@realDonaldTrump) March 7, 2020
"This is a positive development demonstrating the United States' long-standing commitment to the peace process," an Embassy spokesperson said.
"Mick Mulvaney has always had a great personal interest in Northern Ireland and we look forward to continuing to work with him on this and other issues."
Taoiseach Leo Varadkar has also welcomed the appointment, saying on Twitter that Mr Mulvaney had been a good friend to Ireland.
Really pleased Mick Mulvaney has been appointed as US special envoy to Northern Ireland. He has been a good friend to Ireland and understands all the key issues in detail. He'll have a hotline to President Trump when it comes to issues affecting Ireland, north and south— Leo Varadkar (@LeoVaradkar) March 7, 2020
Meanwhile, Sinn Féin President Mary Lou McDonald said US Special Envoys had been instrumental in facilitating and protecting the Good Friday Agreement and subsequent agreements over the past 22 years.
In a statement, she added: "I look forward to working with Mr Mulvaney to ensure that all our agreements are protected and implemented as we navigate our way through Brexit and plan for referendums on Irish unity in line with the Good Friday Agreement."
DUP leader Arlene Foster tweeted that there was "lots of work to do".
The United States has been a loyal friend to Northern Ireland. The appointment of the new Special Envoy will be important in developing that friendship. US is a key market for us. Lots of work to do. https://t.co/sorrr0MvO6— Arlene Foster (@DUPleader) March 7, 2020
The influential Democratic Congressman Richard Neal has welcomed Mr Mulvaney's appointment.
Mr Neal is the chairman of the powerful House Ways and Means Committee which will oversee any future trade deal between the US and the UK.
He said that with the appointment of a new Special Envoy, the United States is demonstrating its ongoing commitment to the region at a critical time, particularly as the implications of Brexit in Ireland, north and south, become known.
Mr Neal said: "I welcome the announcement and believe it could help strengthen relations on both sides of the Atlantic".
Also last night, the White House announced details of next week's meeting between the Taoiseach Leo Varadkar and Mr Trump.
Mr Varadkar will visit the White House on Thursday 12 March for the traditional St Patrick's celebration.
The White House said the two will discuss how to strengthen relations between the United States and Ireland, including the robust economic and cultural ties and joint commitment to maintain the gains of the Good Friday Agreement.
The statement added that Mr Trump was looking forward to hosting the Taoiseach at the annual Shamrock Bowl presentation.
While in Washington, Mr Varadkar will also attend a lunch on Capitol Hill hosted by the Speaker of the House Nancy Pelosi.
Traditionally, the US president also attends the Speaker's lunch but Mr Trump is not expected to do so this year.
Additional reporting: AFP