Play video content 8/27/17 MTV

A distant blood relative of Robert E. Lee publicly denounced racism and white supremacy at the VMAs this weekend ... directly calling out "America's original sin."

Reverend Robert Lee IV -- a direct descendant of the Confederate general -- came onstage Sunday at the MTV award show to call out racism and white supremacy as evil and wrong ... and made a call to action for everyone to stand up against it head on.

Lee said it was his duty to speak out against racism, which he referred to as "America's original sin." He then introduced Heather Heyer's mother, Susan Bro, who announced the winner of the Best Fight Against the System award ... which ended up going to all 6 nominees.