Damian Lillard's exploding rap career just got its first legendary co-sign ... from Common ... who says Dame's skills on the mic are so FIRE ... he'd be down to work with him.
Common was leaving Equinox when we asked him about Lillard's rhyming ... wanting to know if the NBA star actually has the goods when it comes to hip-hop.
A bunch of labels think so ... we already told you Dame's being courted by HUGE record companies ... and he's currently mulling his options.
Common -- himself one of the biggest names in rap -- tells us he's heard Dame spit and and thinks he's absolutely ILL ... so ill he'd be down to personally work with him ... if he ever got the call.
Make the call Dame ... dude's got an Oscar.
Waiting for your permission to load Soundcloud audio.