CIVIC nationalist group Ireland's Future is aiming to fill Dublin's 3Arena for the "biggest ever United Ireland conference".
The group aims to attract 10,000 people to the major venue on Saturday October 1.
3Arena has previously hosted gigs by Bob Dylan, Fleetwood Mac and Elton John.
Ireland's Future chief executive Gerry Carlile said the venue is the largest the group has booked "by some distance".
The group will also launch a 150-page "vision document" for the future of Ireland on October 1 and host a dinner at Dublin's Mansion House that evening.
Mr Carlile stressed that the event was not a rally but a conference which aimed to include anyone with an interest in Irish unity.
He said the group is in discussions with high-profile speakers from the US and European Union.
"We want to reach as far and wide as possible, into the Irish diaspora in America and also the EU," he said.
"The majority of people in Northern Ireland voted to stay in the EU and a united Ireland brings us back into the EU again."
He said the conference aimed to be as inclusive as possible.
"We appreciate that there are so many people that have to be included in this conversation and that want to be included," he said.
"We don't want to put barriers in their way.
"We've always tried our best to make it as easy as possible for people who want to get involved to get involved."
Mr Carlile said the event will be a "scaled up version" of the group's conference in the Waterfront Hall in Belfast in January 2019 but with "elements of surprise".
"The whole discourse has advanced and developed years on from the Waterfront," he said.
"There are more and more people asking more and more questions about what Irish unity means for them and their families.
"It's very exciting. The feedback we are getting is truly phenomenal."
Mr Carlile said Ireland's Future events presently being held in venues across the island every month are "about building momentum ahead of October 1".
He said the 'vision document' will give information about the process of holding a border poll and will cover issues including health, the economy and infrastructure.
Mr Carlile called for an all-Ireland citizens' assembly to discuss constitutional issues ahead of any border poll.
"That will allow us to discuss each other's visions for the future," he said.
"You'll have ordinary citizens from Cork and ordinary citizens in Coleraine joining in one room.
"There should be a joined-up approach from the political world, civic society, trade unions, the business sector and the sporting world.
"We need to move the conversation on to the next level."
