North Queensland star remains in the NRL and joins his brother Ashton at Knights.
Tariq Sims is officially the newest Knight after the club confirmed the forward will head to Newcastle on a two-year contract.
The signing follows former Raiders prop Sam Mataora joining Newcastle on Thursday.
Sims, who will leave North Queensland to join the Knights, has played for Country as well as Fiji.
He has also been selected as an Emerging Blue.
“We are obviously really pleased to sign Tariq, a powerful and competitive forward,” Knights chief executive Matt Gidley said.
“He comes to the club with plenty of football ahead of him but also with a lot of experience.”
“Tariq will bolster our forward pack while also playing a significant role in the development of our young forwards coming through the system.”
The Cowboys released Sims to allow him to join the Knights.
Sims has been touted at one of the best young forwards to be seen in the game in the past five years, but injuries have curtailed what he is capable of.
However, the Knights be looking to get the best out of Sims again, and if they can do that, then they have a valuable piece for their forward pack for perhaps beyond his current two-year deal with Newcastle.