Donald Trump has called the Taoiseach Leo Varadkar to congratulate him on his "great victory".
The US president has spoken to the Taoiseach on the phone, for the first time since Mr Varadkar took office.
Reporters in the Oval Office said Mr Varadkar kept the US president waiting on the phone for around 90 seconds before answering.
There was speculation as to why Trump was kept on hold, and it was revealed that this was to allow time for Mr Varadkar to finish answering questions in the Dáil.
During the phone call today, President Trump requested a broader explanation on how the border works between Northern Ireland and the Republic of Ireland - something which he also asked of former Taoiseach Enda Kenny when he met him last St Patrick's Day.
Trump also invited the Taoiseach to attend the annual St Patrick's Day events in Washington next March.
However, a visit by Trump to Ireland was not brought up during this conversation, despite Kenny extending the invitation during his visit.
Both leaders discussed the undocumented Irish, migration, Brexit and the movement of goods and citizens across the border, climate change, free trade, and Irish inward investment in the US.
They also discussed the North's peace process.
Mr Varadkar also held a call with the British Prime Minister, Theresa May, today where they talked about efforts to restore the Stormont Executive ahead of Thursday's deadline, and the agreement between the Tories and the DUP.
The Prime Minister explained that the DUP will support the Conservative Government on votes on the Queen’s Speech, the Budget, and legislation relating to Brexit and national security.
Mrs May went on to say that the agreement makes clear that the UK "remains steadfast" to their commitments in the Belfast Agreement and in governing in the interests of all parts of the community in North.
A spokesperson for the Prime Minister said: "They confirmed their joint commitment to restore a Northern Ireland Executive as soon as possible and agreed to engage closely, and work with the parties in Northern Ireland, to bring back political stability and a strong voice at Stormont.
"The two leaders also spoke about their willingness to continue close cooperation as the UK embarks on leaving the European Union."