Paris Jackson is adamant, the Instagram account posing as her that changed its last name to Jackson Castellaw isn't the real deal ... and she wants it shut down.
In a video posted to her bf Chester Castellaw's alleged page, Paris asks fans to help her get the impostor account -- which has racked up more than 200k followers -- removed. She claims she does not have a public profile.
It's interesting ... the video doesn't address marriage rumors but a source close to Paris says the two aren't married.
As TMZ reported ... fans began to buzz about Paris and her 18-year-old bf tying the knot after his last name was added to an IG account claiming to be her.