20 year-old Watson expressed his delight at extending his contract with the Tricolours.
"I'm very excited to extend my time with the Roosters," said Watson.
"I'm learning so much from Robbo (head coach Trent Robinson) and the coaches, and this is where I want to build a career.
"I know I still have a lot of improvement in me, and hopefully I'll keep learning and improving and secure an opportunity to play some good footy for the Roosters," he added.
Robinson said it was exciting to have Watson extend his arrangement with the club.