Fianna Fáil is to share the leadership of the Union for a Europe of Nations group in the European Parliament with the Italian post-fascist Alleanza Nazionale.
The Munster MEP Mr Brian Crowley will be co-president of the group with Allianza Nazionale's Ms Cristiana Muscardini.
Mr Crowley insisted yesterday that he would be the group's de facto leader, representing it at meetings with other groups in the parliament and in talks with the Commission and the Council.
"The practical outcome is that I will be the acting president," he said.
The group yesterday agreed to change its name and revise its political charter to reflect the addition of some parties from central and eastern Europe. Mr Crowley said the changes would help the group to shed its image as a right-wing, Eurosceptic element in the Parliament.
"We want to move away from the media perception of us as a Eurosceptic group.
"We consider ourselves to be in the mainstream of European politics," he said.
Apart from Fianna Fáil and Alleanza Nazionale, the group includes members of Poland's right-wing Law and Justice Party, Lithuanian and Latvian conservatives and a far-right Danish MEP.