Sinfield hopes to celebrate his new deal with a Grand Final win

Sinfield, who has been with Leeds since he was 13, will be 31 when his new contract finishes in 2011.

"I am delighted," said Sinfield. "I have said for some time that I wanted to end my career here."

The news is a major boost for the club coming on the eve of their Grand Final meeting with St Helens at Old Trafford.

Sinfield won the Grand Final with the Rhinos in 2004 and will become the first Leeds captain to lead the club to two championships if they defeat Saints on Saturday.

The Oldham-born Sinfield is the third highest points scorer in the club's history and is on the verge of making history.

606: DEBATE Are you happy Sinfield has signed a new deal?

The team's goalkicker, Sinfield will become the first Leeds player to appear and score in every game played by the team in a season if he registers on the scoreboard in the final.

He added of his new deal: "I never dreamed when I first signed for the club when I was 13 that I would be here so long.

"I am not a Yorkshireman but I am very much a 'Leeds lad' and I feel at home here just as much as the many Leeds-born and bred players we have in our side."

Leeds coach Tony Smith will preside over his final game in charge of the club at Old Trafford before taking up his position as Great Britain boss on a permanent basis.

Smith said of Sinfield: "He has achieved so much already in his career by I believe his best years are still to come.

"He is a tremendous leader and will continue to be so. Leeds runs through his veins and his commitment to the club will be an important factor in retaining this group of players for the future."