Formerly a barrister practicing in Ireland and the British Virgin Islands, Robert O'Reilly (pictured) has latterly been an adviser to current ambassador Robin Barnett and his predecessor Dominick Chilcott.
O'Reilly has now joined Cicero as a director, and officially opens Cicero's Dublin office on 1 February.
He will provide public affairs and corporate comms support to domestic and international clients of the Top 150-listed agency.
Helena Walsh, executive director at Cicero Group, said: "Brexit presents a unique set of operational, market access and regulatory challenges to businesses against a backdrop of continued political uncertainty."
O’Reilly said Brexit was "the biggest challenge to Ireland’s economy in a generation", and claimed: "With expert teams across London, Brussels and now Dublin, Cicero offers incomparable expertise for organisations at home and abroad who are grappling with a whirlwind of political upheaval."
The possibility of Brexit creating an opportunity for Dublin to improve its standing as a regional business hub at London's expense, and in turn create opportunities for the PR industry in the country, had been mooted since the run-up to the 2016 vote for the UK to leave the EU. Since the vote, issues including the country's land border with the UK have proven complex and emotive topics.
Cicero is not the first agency to look to Dublin post-Brexit; Hanover set up in the city almost exactly 12 months ago, while US boutique Wachsman also opened in the Irish capital last year, and now has 12 staff in that team.
Elsewhere, Weber Shandwick UK's corporate, financial and public affairs MD Ben Burton has recently moved to a new job in Ireland.