Bella Thorne to Miley Fans -- Patrick Schwarzenegger and I Are Just Friends, I Swear!!! (PHOTO)

Bella Thorne knows what happens when you mess with Miley Cyrus and her man ... so she's sending a preemptive message to Miley's fans.

Bella and Patrick Schwarzenegger were photographed leaving the Mud Hen Tavern in Los Angeles Wednesday night ... no hand holding or kissing ... but lately when Patrick gets photographed with another girl, Miley fans go berzerk.

Bella is no fool ... she posted a photo of her and Patrick during dinner and captioned it, "With my homie @patrickschwarzenegger if you aren't already following him you should :)) disclaimer *** we are just friends :)"

Hopefully that's enough to keep the wolves at bay.