Sinn Féin's Mitchel McLaughlin is to give up his Derry assembly seat to contest the unionist stronghold of South Antrim in the proposed March assembly elections.
Mr McLaughlin, the party's general secretary, was expected to be nominated for the South Antrim seat at a Sinn Féin election convention last night (Thursday).
His Derry assembly seat will be contested by former Sinn Féin mayor Lynn Fleming and former republican prisoner Martina Anderson. The other Sinn Féin seat in Derry is held by Raymond McCartney.
In a shock move, Mr McLaughlin said he hoped to build on the efforts of high profile Sinn Féin member Martin Meehan in the 2005 assembly election.
One of Sinn Féin's most senior politicians, Mr McLaughlin is a former leader of the party on Derry city council. In the last general election, he was defeated by SDLP leader Mark Durkan for the Foyle seat formerly held by John Hume.
South Antrim is a mixed rural/urban constituency on the north eastern banks of Lough Neagh. It includes part of Antrim district council and Newtownabbey district council.
The constituency's largest town is Ballyclare but it also runs into the suburbs of Belfast, including Glengormley. The only nationalist seat in South Antrim is held by SDLP member Thomas Burns.