Belfast, Northern Ireland (CNN) -- Former IRA local commander-turned-politician Martin McGuinness will have to defeat an openly gay senator and a popular Labour party politician, among others, if he is to become president of the Republic of Ireland, it emerged Wednesday as the election ballot was finalized.
Sen. David Norris completed an extraordinary comeback Tuesday, securing the political backing he needed to get onto the ballot after withdrawing over a sex scandal in August, then changing his mind and jumping back into the race.
He leads the field, according to an opinion poll published in the Sunday Business Post this week, followed by Michael D. Higgins of the Labour Party and McGuinness, the Sinn Fein politician who stepped down as deputy first minister of Northern Ireland to run for president of the republic.
There will be a record seven candidates in the election October 27.
Norris -- tipped to be the country's first openly gay head of state -- got onto the ballot, thanks to an 11th-hour intervention by his rival Higgins.
Ahead of a vote by Dublin city councilors, Higgins recommended to Labour colleagues they facilitate the entry of Norris to the presidential race "in the interests of democracy."
Higgins criticized the nominations procedure, calling it archaic. To stand in the election, candidates need the backing of four local authorities, or 20 parliamentarians.
The lifeline from Dublin marks a remarkable return to the presidential contest for Norris. At the start of August, he withdrew from the race following revelations he had written letters seeking leniency for a former partner convicted of the statutory rape of a 15-year-old boy in Israel.
In recent weeks, Norris reconsidered due to what he called "overwhelming public support."
The independent candidate admitted Tuesday it was an "extraordinary comeback" to get his name on the ballot paper.
"If I can make this extraordinary comeback, then this country can make an equally extraordinary comeback and I hope to be there at the head of it," Norris said.
Earlier on Tuesday, former Eurovision song contest winner and ex-member of the European Parliament, Dana Rosemary Scallon, received the backing she needed from a fourth local council to run, also as an independent.
The seven-candidate list is now complete and Norris appears to be a frontrunner. A weekend opinion poll showed him ahead with 21% support, Higgins second with 18% and McGuinness third with 16%.
Dana Rosemary Scallon finished bottom in the opinion poll. The other candidates in the election are Gay Mitchell of the main ruling party Fine Gael and two more independents, Mary Davis and Sean Gallagher.