Los Angeles can collectively exhale. LeBron James is officially a Laker.
The club announced late Monday afternoon that James has put pen to paper on the reported four-year, $US154 million ($A204 million) deal.
It came just as James' representation, Klutch Sports Group, tweeted an image of James, agent Rich Paul and Lakers general manager Rob Pelinka confirming the news.
"Today is a great day for the Lakers organisation and Lakers fans all over the world to welcome LeBron James, a three-time NBA Champion and four-time NBA MVP," Lakers president of basketball operations Magic Johnson said in a statement.
"LeBron is special. He is the best player in the world. He loves to compete and is an awesome leader who is about winning and making sure that his teammates are successful.
"The Lakers players are excited to have a teammate who has been to nine NBA Finals. It's a huge step closer to returning the Lakers to the playoffs and to the NBA Finals."
James, 33, has averaged 27.2 points, 7.4 rebounds and 7.2 assists per game in 1,143 career contests.
He also has been named NBA Finals MVP three times.
Last season was his first in which he played in all 82 regular-season games, and the eighth in a row in which his team advanced to the Eastern Conference finals.
This marks the first time James will play for a team in the hotly contested Western Conference, which includes heavyweight teams such as the Golden State Warriors and Houston Rockets.
James spent his first seven seasons with the Cleveland Cavaliers, his next four seasons with the Miami Heat, and his past four seasons back at home with Cleveland.
Shortly after agreeing to terms with James last week, the Lakers agreed to deals with free agents Rajon Rondo, Lance Stephenson and JaVale McGee, and also agreed to bring Kentavious Caldwell-Pope back.
Those deals were officially announced earlier this week.