Watts has played 47 games for the Black and Whites, after joining the club from Hull KR in 2012.
“I am over the moon to be able to sign a new contract at the club, I was obviously looking to tie down my future down and I’m really glad that it’s going to be here,” said the 24-year-old.
“I want to be a part of what is going to be happening over the next couple of years at the club. I’m really looking forward to getting stuck in there with the lads for the rest of the year and finishing on a high note.
“We have got something good growing here with a solid group of lads, and it is also clear to see the intent we have next year with the signings of Leon Pryce and Marc Sneyd so I feel we are moving in the right direction.”
“Hull is a great city for rugby league and I am so pleased to be able to secure my future here.
“To have been given the opportunity to come to Hull in the first place, which is obviously a massive club with big aspirations was extremely pleasing, and when I first signed I was keen to be a part of those long term goals.
“We have a young squad here and I now look forward to helping the club achieve those targets.”