A run‐on sentence is two or more independent clauses joined together with insufficient punctuation. This means that there are two or more complete sentences fused into one sentence. Use a colon: a ...
Braveheart did it, Adele does it. While I did it then, splicing two sentences into one, snubbing the semicolon to mash two time-zones, my heresy enacted by that intermediary comma. Grammarians know ...