The Taoiseach has said his past criticism of Bertie Ahern was the product of "a point in time".
In 2008, Leo Varadkar compared Bertie Ahern's defence at the time to a "John Gilligan" tactic.
Mr Ahern has rejoined his local Fianna Fáil branch in Dublin Central - 10 years since he resigned from the party in the wake of the Mahon Tribunal.
Speaking in Brussels today, the current Taoiseach was a lot softer in his words.
"I think that was at a particular point in time, and if you look at the totality of Bertie Ahern's career; let's not forget that he was one of the architects of the Good Friday Agreement and that's something we're going to recognise in a few months' time.
"I don't think anyone can diminish the role he played, but who is a member of Fianna Fáil is a matter for Fianna Fáíl."
Former Fianna Fáil junior minister Conor Lenihan has described Mr Ahern's return as "a very welcome thing".
“I think, in particular, his skills of organisation, which ultimately, when I was elected in 1997, won us three successive general elections, will also be a huge plus for the party because we really do need people of great wisdom like him advising the party on its electoral and on its candidate strategies and indeed on its policy matters,” he told Newstalk Breakfast.
“Of course there will always be criticism, that is the nature of politics, but I think the most important thing to remember here is whenever I am out and about, he is hugely welcomed and hugely popular still.
“I think there needs to be a distinction made between what we might call opinion as it is expressed online and in media and what the ordinary public think. Anytime I have been out and about with him and meet him socially or otherwise, he is mobbed with people.
“People are always more than keen to get up and shake his hand. So, it is a slightly different reality in fact, he is still, in my view, quite popular with the public.”
The people of Mr Ahern's locality Drumcondra reckon his return to Fianna Fáil could be in anticipation of the 2025 presidential election.
One person told Newstalk: "I'd say there has to be some reason, are they thinking of a tilt at the presidential election coming? How they'd feel about it now down here [Drumcondra], I'd say a lot of people have changed [their opinion], moved on."
Another said: "I don't think he'd be any better than any of the rest of them, and what's come to light in the last while about their properties and not declaring this and not declaring that... they are no better than Bertie."