The DUP is losing one of its key advisers, strategists and speech writers to a public relations firm.
The party stressed there had been no falling out with Richard Bullick, who has been intensively involved in a number of crucial negotiations during the past 15 years.
A private individual who would not be well known outside the political village at Stormont, the £91,000 a year special adviser helped manage the transition of the DUP over recent years and the expansion of its support base.
The qualified barrister was named by former Enterprise Minister Jonathan Bell - who lost his seat in the March Assembly election - as having witnessed a "hostile" meeting with DUP leader Arlene Foster.
However, Mr Bullick subsequently denied seeing any heated exchange between Mr Bell and Mrs Foster.
He was also said to have been "intensively involved" in the Nama loans sale process, but has insisted he never had "any understanding" that two businessmen stood to be paid as part of any deal.
Giving evidence to a Stormont inquiry, Mr Bullick said he had a series of meetings with Frank Cushnahan, who sat on Nama's local advisory committee, and leading solicitor Ian Coulter between September 2013 and April 2014.
More than 20 years earlier, he was a junior barrister to Jim Allister and was involved in the DUP's decision to lure Mr Allister back from the legal world to replace Ian Paisley as an MEP.
Mr Allister later quit the DUP for a second time and set up his own party, the TUV, in reaction to the power-sharing deal with Sinn Fein at St Andrews.
Now Mr Bullick is to be head of public affairs at the commercial PR firm MCE, which said yesterday it was "delighted" to appoint him.
Managing director Paul McErlean added: "Richard is widely respected and he has a wealth of experience and insight at all levels of government, which we believe will be of real benefit to our clients.
"This appointment shows that the brightest and best people can be attracted to public relations and public affairs, thereby lifting the standard of our services and the value we bring to our clients."
The DUP said it was "sad that he is moving on" but stressed that he left on good terms.
"Richard is a very able and talented person who has been involved in working for the party since 2000 and has had a very significant input into the party since then," a spokesman explained. "Everyone in the party recognises the talent he has."
The spokesman added that Mr Bullick remained "very supportive" of the party and was expected to continue to "offer advice and guidance" in the future.
Sinn Fein leader Gerry Adams has called the forthcoming General Election an opportunity for the party to "challenge the disaster that is Brexit", and accused both unionists and the Government of ignoring the "disastrous" impact of the referendum decision for the UK to leave the EU across the island of Ireland.