De Gois has been linked to the Sharks since it was confirmed St George Illawarra Dragons coach Wayne Bennett would move to the Knights next season.
It is understood De Gois agreed to the deal two weeks ago, after earlier being told he was not wanted at Newcastle beyond this season.
The talented 26-year-old played one of his best games for the Knights on Sunday to win the man of the match award in the 18-10 win over Sydney Roosters at Ausgrid Stadium.
He is well known to Cronulla coach Shane Flanagan and the Sharks’ staff after playing at the club in 2007-08.
The Sharks’ recruitment drive has gathered momentum in recent weeks, with De Gois to join Bryce Gibbs, Andrew Fifita (Wests Tigers) and Jeff Robson (Parramatta Eels) at the club next year. Sam Tagataese has already moved to Cronulla after shifting mid-season from the Gold Coast Titans.
De Gois would not comment on his future but said, with several players set to move on when the Bennett era begins, the sixth-placed Knights are determined to make the most of 2011.