CIARA'S NBA BALLER BF AMARE STOUDEMIRE CAUGHT CREEPING . . . WITH ANOTHER FAMOUS CHICK!!!

There's some NBA drama in New York . . . just in time for the playoffs. MediaTakeOut.com told you last week that NBA all star Amare Stoudemire and R&B singer Ciara are OFFICIALLY DATING . . . and they've MOVED N TOGETHER.

Well that hasn't stopped Dame Dash's COUGAR ex-wife Rachel Roy from putting the moves on CiCi's man.

According to a ROCK SOLID SNITCH Amare and Rachel have not only a professional relationship (they're doing a clothing like together), but a PERSONAL one as well.

Tells the insider, "Rachel likes Amare - but more importantly she likes the spotlight. She sees the shine that LaLa gets by being with Carmelo - she wants the same."

And MediaTakeOut.com's tipster continued, "If I know Rachel, she won't stop until she's got Amare."

So we know what you're thinking . . . where's Ciara as her man is being STOLEN UNDER HER NOSE??? Well . . . she's on tour in Australia!!!