Scan of an EW article about the upcoming Prom episode:
And not only the video promo already evidences that the sexual tension between Stefan and Elena during their dance is off the charts indeed, but the author of the article also mentioned it on Twitter:
Stefan/Elena have loads of chemistry… especially post-breakup.
Finally, to definitely remove any doubt, it has been confirmed by @cadlymack that it’s Elena dancing with Stefan, and not a Katherine’s or Silas’ impersonation.
So, Stelena fans, let’s just rejoice for such a rare and precious moment to enjoy in this mess of a season!