Mark Adair has confirmed he's opted to join CIYMS for the 2019 season.
The 22 year-old former Irish youth international had attracted attention from at least four leading Premier sides, but has decided to join the champions.
"I want to win trophies," the Northern Knights all-rounder told CricketEurope.
"CIYMS are an exciting side who have proved they can be successful in competitions," added Adair.
The Belmont side recently announced the signing of South African Obus Pienaar as their overseas professional for the 2019 campaign, and are assembling quite a formidable side as they attempt to defend their league title.
Former Warwickshire player Adair joined his home town club Holywood after being released by the English county at the end of the 2017 season.
He enjoyed a successful season in the second tier of NCU cricket, taking 39 wickets at 12.36, as well as scoring 531runs at 29.50.