Chad Townsend will join North Queensland on a three-year deal after becoming the first domino to fall in what shapes as a long year of halves movements in the NRL.
Townsend on Wednesday told Cronulla teammates he would be leaving the Sharks at the end of the year, making 2021 his last of nine seasons at his junior club.
With an option in his favour to remain at Cronulla for next season, Townsend's decision not to activate that comes just a week after coach John Morris was axed.
The 30-year-old Townsend met with incoming Sharks coach Craig Fitzgibbon on Tuesday and told him of the Cowboys offer, before telling North Queensland officials he was in.
His signature comes as a significant coup for the Cowboys, who had been searching for a replacement for the medically retired Michael Morgan.
"We have made no secret of our intentions to secure a senior half after we lost our captain Michael Morgan to retirement," Cowboys coach Todd Payten said.
"We were looking for a composed organising halfback who can steer the team around the park and I believe we have found that in Chad.
"He is a gifted kicker of the football, tackles well and is a strong voice on the field, which were three areas we highlighted when entering the market for a half."
The 2016 premiership winner's move will have significant flow-on effects.
The Cowboys had initially gone after the services of South Sydney half Adam Reynolds, but that is now out of the question.
Reynolds is yet to be offered the multi-year deal he wants at the Rabbitohs, and is still sounding out the market for next season.
A shift to Cronulla is now looking like an increasingly likely option.
The Sharkshave Shaun Johnson and Matt Moylan off contract this year, with both an option to play five-eighth if Reynolds is signed.
However, Johnson was a vocal supporter of Morris at the Sharks and has previously said he wanted to play under him there next year.
It's believed most clubs are waiting to see how he returns from a ruptured achilles in coming weeks before approaching the 30-year-old Kiwi.
Townsend's move north will quash any rumours about Luke Brooks leaving Wests Tigers to head to Townsville, a move both the player and his club had denied.
The Tigers have signed Jackson Hastings for next year but he is expected to play on the ball at lock.
Meanwhile, Parramatta halfback Mitchell Moses is another No.7 still not locked in for next season, yet to activate an option in his favour to stay at the Eels.
St George Illawarra's Corey Norman, Brisbane's Anthony Milford and Gold Coast's Ash Taylor are among other playmakers still unsigned for 2021.