Rebecca Black was only 13 years old when "Friday" became a YouTube sensation ... for all the wrong reasons.

The bullying afterwards became so bad that Black was forced to quit middle school in 2011 .

Now 19, the singer has returned with a new single, "The Great Divide." In one version of the music video, she delivers a teary message to fans.

"I just wanted to prove everyone wrong .... but now that it's here I have that within myself and I don't need that anymore," she says.

"I think what I'm also most excited for is there are some of you I've seen stick with me for four or five years now and you've always been so excited and so patient with me, so before the music video starts I wanted to say thank you to you guys."

The EDM-tinged single prompted plenty of positive comments from fans, who wrote things like, "Honestly, this is so inspiring!" and "OMG Rebecca DON'T CRY! Im so happy & proud of you & your success!"