Jack Johnson leads all Kings defencemen with 31 points in 41 games this season. ((Harry How/Getty Images))

The Los Angeles Kings have signed Jack Johnson to a seven-year contract extension that ties the young defenceman to the club through the 2017-18 season, the team announed Sunday.

Terms weren't immediately disclosed, but multiple reports said the deal is worth $30.5 million US.

Johnson, 23, leads all Kings defensemen, and ranks sixth among all NHL blue-liners, with 31 points in 41 games this season.

The University of Michigan product, who was drafted third overall in 2005 by Carolina, set career highs last season in goals (eight), assists (28), points (36) and games played (80).

The length of Johnson's deal matches the one the Kings gave to centre Anze Kopitar, their leading scorer the last four seasons, in October 2008.