Johnathan Thurston has a handshake deal with the North Queensland Cowboys that will see him remain at the club in an official capacity long after Friday night's farewell.

As more than 20,000 Cowboys fans get set to farewell one of the game's greatest players, Fairfax Media can reveal Thurston will remain in an ambassadorial role until at least the end of 2022.

Not done yet: Johnathan Thurston will stay on at the Cowboys as an ambassador for the club until 2022. Credit:AAP

Cowboys football director Peter Parr said Thurston and chairman Laurence Lancini would thrash out the finer details of the deal after the season.

"There's a deal that's been done, the chairman and Johnathan have shaken hands and what it actually looks like we'll worry about after the season,'' Parr said. "We want him to stay part of the club, there's no doubt about that.