A Lisburn and Castlereagh councillor has quit the Green Party and joined the SDLP.
Simon Lee was elected in the local government election in May 2019, when the party saw a rise in its vote share and number of councillors.
But it faced significant defeat in the assembly election this year, when both sitting MLAs lost their seats.
Party leader Clare Bailey, who was South Belfast MLA, and North Down's Rachel Woods failed to be re-elected.
The Belfast Telegraph first reported that Mr Lee had defected to the SDLP.
In a statement released by SDLP, Cllr Lee, who represents Castlereagh South, said the move was "a big decision" but he felt like the party was a "perfect fit" for him.
"Over the last number of years I've also been more attracted to the party's work on building a new Ireland," he added.
SDLP leader Colum Eastwood tweeted that he was "delighted" the councillor was joining his party's ranks.
SDLP Claire Hanna MP said she was "absolutely chuffed" to welcome Mr Lee, describing him as "first class public representative, an incredibly hard worker and a really lovely guy".