Good news for Blake Griffin ... his girlfriend is pregnant ... again!
The NBA star was spotted out in Hawaii this week with his longtime GF, Brynn Cameron. The two already have one son together who was born back in 2013.
Now, it seems the kid's getting a new sibling -- because Brynn is clearly pregnant again!
FYI, Brynn -- a former college basketball player -- also has another child with ex-boyfriend Matt Leinart.