His days with the Lakers are over ... but ex-NBA player Kareem Rush is still gunning to sell out the Staples Center ... as the next big superstar in pop music.
The 34-year-old tells TMZ Sports he's focusing on a singing career -- "I'm a cross between Timberlake and Maxwell."
Rush has been working on his craft for years ... and even dropped a single back in 2010 ... before he officially retired.
But now that he's done hoopin', Rush says he's putting everything he's got into music -- and plans to drop a brand new album later this month.
In fact, Rush says he also has his sights set on getting another ex-NBA player to join him in the studio ... one of the biggest stars in the history of the sport.