LAUREN LONDON NOT Dating Diddy ... NIPSEY'S STILL MY KING!!!

Lauren London's making it perfectly clear she's NOT dating Diddy or anyone else for that matter ... 'cause it'll be her and Nipsey Hussle 'til the end of time.

Lauren took to Instagram Thursday and posted a picture of the late rapper and captioned it "Still His! King Ermias! Never Forget!" And, for those who didn't get the message the first time she took it a step further and said, "Stop f***ing playing with me and my name. Now let me get back to healing."

The actress felt compelled to quash rumors she and Diddy are dating after Diddy reportedly posted -- and then deleted -- a couple of black and white pics of him and Lauren.

Diddy initially captioned the Instagram pics "#lostfiles ... @laurenlondon❤️." The pics, BTW, were taken at