Tommy Talau was rated the best prospect at Wests Tigers since James Tedesco and has now agreed to another two seasons.
The 19-year-old is expected to take on a centre position in 2020 after Esan Marsters moves to North Queensland.
He made his NRL debut in round 22 this year against Manly and has only played one first grade match.
“I’m really happy to be able to extend my time at the club,” Talau told the club's website.
“I’ve had an unreal experience so far — making my first-grade debut — and I’m really excited to continue my journey and see where 2020 takes this team.
“I think this club is really building a strong foundation and has helped me grow a lot so I’m looking forward to where things so for us in the next few years.”
Talau's would have been off-contract after next season but will now stay until the end of 2022.
He played in the SG Ball final last year for Canterbury and was the top tryscorer before moving to Wests Tigers.