With the scale of some of the performances, the moving around and dancing, it seems almost impossible acts could sing live at the same time.
However, Eurovision rules say acts must sing live. That said, no live music performances are allowed.
Eurovision rules clearly state "all songs shall be performed live on stage with a recorded backing track". Backing tracks may contain backing vocals, as well as a melody, however the vocal shall not "replace or unduly assist the lead vocals" during the live performance.
