12-10-2022, 07:57 PM
From the 2019 rules for the contest - similar to 2017 and 2018 too
web.archive.org
Quote:Backing tracks only
Contestants and Artists shall perform the songs live on stage, accompanied by a recorded backing-track only (without live instruments). The Backing track shall contain no vocals of any kind or any vocal imitations aiming at replacing or assisting the live/original voice of the Contestant(s) […].The Host Broadcaster and the ESC Executive Supervisor shall verify respect for this rule.
web.archive.org