Ms Bernadette Sands-McKevitt, a sister of the 1981 IRA hunger-strike victim, Bobby Sands, and a dissident republican, Mr Michael McKevitt, are expected to marry today. The couple have lived together for some years near Dundalk, Co Louth, and have two children.
Both are leading figures in the 32-county Sovereignty Committee which has alleged links with the Real IRA, the group that admitted responsibility for carrying out last year's Omagh bombing in which 29 people died and more than 200 were injured.
Ms Sands-McKevitt, who changed her name by deed poll, last night denied the wedding plans. But local reports indicated she and Mr McKevitt would marry at Dundalk registry office.