I don't know if he is a dancer, but I think it was just an improvised thing, because there were 5 or 6 men dancing behind her and they were all wearing normal clothes. But I don't know where to find a video of it... If I remember correctly, Blonde was not among the songs that could be filmed by fans, so everything I know about that come from Skeleton's IG account.
Edit:
I took a quick look at his profile and there is this photo:
