Presidential candidate and Irish-American citizen Dana Rosemary Scallon has denied covering up her dual nationality, insisting it will be an advantage to the country if elected.
Although the Euro-sceptic former MEP claims she cannot remember the wording of an oath of allegiance she swore, she insisted securing the green card does not impinge on her Irish nationality.
"I have dual citizenship," she said. "Ireland, Israel and Canada share the advantage of being allowed to have joint citizenship. For citizens of these three countries, there is no conflict in holding a US passport and a passport of these countries."
The US state department says that the US government recognises that dual nationality exists but does not encourage it or require a person to choose one citizenship over another. Ms Scallon has admitted securing the dual nationality in 1999.
She rejected suggestions she ever tried to hide her US citizenship, a claim reportedly made by her sister Susan Stein during a court case in the US in 1998 during a bitter row over ownership of some of the singer's recordings.
Ms Stein told the court she discussed her sister's citizenship with Dana's husband, Damien Scallon, and their brother John Brown, Dana's adviser in her current presidential campaign, when the singer first stood for the presidency in 1997.
But Dana has dismissed the claim insisting she did not become a US citizen for another two years. The religious singer said she was not present for any conversation discussing her citizenship as impediment for her role as a candidate, nor did her brother or husband recollect such a conversation.
"I think it's a very low ebb that the media would use a family dispute, which is painful, which we have settled, in order to paint me in some way as deceiving the people of this country," she added. "There's not one family who hasn't had difficulties, and we worked our way through it."
The wording of the oath for US citizenship states allegiance to America and renounce allegiance to all other states. US immigration sources said there is a special arrangement between Ireland and the US that a person applying for citizenship can keep their Irish citizenship.
"If you look at the wording of the oath it's a couple of hundred years old, old testament language," he said. "If you take it literally you would have to give up your Irish citizenship. But it's moved on since then."