European Council president Donald Tusk is in Ireland today (March 8) to meet Taoiseach Leo Varadkar.
They will discuss Brexit negotiations, the European Commission's draft withdrawal agreement and suggested guidelines for the future relationship between the EU and the UK.
The pair will also consider key economic issues during the talks at Dublin's government offices.
Tusk's visit comes before EU heads of state gather for the European Council summit on March 22-23, where they will discuss Brexit.
Ireland's foreign affairs minister Simon Coveney has suggested the EU could block Theresa May's plans to maintain a soft Irish border while leaving the customs union.
One fallback option is the UK would have to accept keeping Northern Ireland in an effective customs union with the EU.
This is Mr Tusk's second visit to Ireland in three months. He has already pledged that the EU will stand with the Republic on the Irish border issue and Dublin's efforts to ensure frictionless passage of people and goods.
In contrast, Northern Ireland's position post-Brexit is to support Britain's exit terms and a transition deal. The Democratic Unionists, the largest party in the Northern Irish assembly and Theresa May's key supporter at Westminster, are adamantly opposed to any settlement distinguishing Northern Ireland's EU trading relationship from the rest of the UK's post-Brexit.
Varadkar will also hold a separate meeting today (March 8) with the secretary general of the Organisation for Economic Co-operation and Development (OECD), Angel Gurria.
Discussions will cover the OECD's latest economic survey of Ireland and the potential for deeper Ireland-OECD co-operation.
Meanwhile Robin Walker, a minister in the Brexit department, is due to meet Gibraltar chief minister Fabian Picardo today (March 8), and Cabinet Office minister David Lidington is hosting a meeting of the Joint Ministerial Committee with representatives of the devolved administrations.