A woman is suing the Belfast-based Sunday World for breach of privacy over a story which said she was a radio presenter's 'secret mistress".
Her lawyers claim the case could have 'wide-ranging implications for privacy cases in the UK and Northern Ireland".
Roberta Campbell is already suing for defamation over the piece which appeared in July 2008 and which reported that a sports car had been set on fire outside the Belfast home of Downtown Radio DJ Dougi Marshall.
Now she has amended her case to include an additional claim for breach of privacy.
Marshall has already received an apology in open court about the story and damages.
Cambell's solicitor, Andrew Millar of Belfast law firm R P Crawford and Co, said she was suing because the article referred to her as "a current flame of Mr Marshall" and as the "presenter's secret mistress", and contained a photograph of her under which it said "Roberta Campbell is having an affair with Dougi".
He said: "We suggest that these words in their ordinary meaning wrongly suggested that our client was involved in a love affair which was dishonest and that she was a deceitful person, lacking in moral scruple and further that it wrongly suggested that she was unchaste in her relations with men."
A judge at the High Court in Belfast yesterday last week gave Campbell permission to amend her case to include the privacy claim.
The court heard that there were parallels to the case over press intrusion brought in the European Court of Human Rights by Princess Caroline of Monaco.
Millar said: "The breach of privacy aspect of the claim relates to the gratuitous publication of our client's address, details of the cars owned by her, that she was a dog lover and also in relation to the publication of a photograph of our client which was taken without her express or implied permission.
"Our client is a private individual who is not famous, notorious or in the public eye and these are matters of which our client had a reasonable expectation of privacy.
"The breach of privacy aspect of our client's claim could have potentially groundbreaking and wide-ranging implications for privacy cases in the UK and Northern Ireland."