DUP firebrand Ruth Patterson has sparked speculation after attending a public meeting organised by her party's nemesis, Jim Allister.
The Belfast councillor set tongues wagging by appearing at the rally in the Shankill addressed by the hardline Traditional Unionist Voice leader.
It is virtually unheard of for a DUP representative to be present at a rival party's event – and could result in disciplinary action against her.
Mrs Patterson is already facing potential censure within the party if she is convicted of charges over an offensive posting on Facebook to which she pleaded not guilty to after apologising for the remarks.
Police are investigating how Mrs Patterson received a post on the social network which envisaged the fictional deaths of senior Sinn Fein members during an imaginary attack on this summer's controversial Co Tyrone commemoration of two IRA men killed by their own bomb.
It was Mrs Patterson's response which led to her arrest by police in August and subsequent charges. Replying to the original post, she wrote: "We would have done a great service to Northern Ireland and the world."
She later apologised for the comments.
Mrs Patterson was not contactable yesterday, when she attended a memorial service to mark the anniversray of the 1993 Shankill bombing.
The DUP was making no comment last night and insisted it was unaware the 57-year-old councillor was present at the TUV event on Tuesday night.
The former Belfast deputy Lord Mayor did not speak during the event, but talked privately with many of those attending, including TUV supporters.
A senior DUP source said he could see no reason why Mrs Patterson would want to leave the party.
"The broad feeling within the party is supportive of Ruth and that she has been fairly harshly treated," the source added.
A TUV spokesman confirmed: "It was a TUV-organised public meeting which Jim addressed.
"Ruth did not address the meeting but spoke to people socially before and after. It is for her to answer any questions about why she was there."
There is no love lost between the DUP and TUV, exemplified most recently after a bitter spat in the Assembly when First Minister Peter Robinson attacked Mr Allister over a family will.
Speaking during Assembly question time, Mr Robinson alleged Mr Allister had been an executor of the will and had sold land to Fermanagh "republicans". But the jibe backfired on the DUP leader after it emerged Mr Allister had not been executor, and the family involved had no known political views.
The TUV leader demanded an apology, which has not been forthcoming. Mrs Patterson's attendance at the TUV event, in light of the spat, is unusual.
Mr Robinson and Mr Allister were once firm allies within the DUP.
Belfast councillor Ruth Patterson has appeared in court charged with sending an electronic message that was grossly offensive. It related to a Facebook comment over an imaginary attack on a republican parade in Castlederg and Mrs Patterson's lawyer has said she will be contesting the charge.