“Our musicians wear body armour instead of tuxedos,” he told stars including Lady Gaga and Justin Bieber, referring to the ongoing war with Russia.
“They sing to the wounded in hospitals, even to those who can’t hear them. But the music will break through.”
He urged musicians to “fill the silence” left by Russian bombs “with your music”.
“Support us in any way you can, but not with your silence,” he continued. “Fill the silence with music.”
The video message was played ahead of a performance by John Legend of a new song, called Free.
The US star was joined on-stage by Ukrainian musicians Mika Newton and Suzanna Iglidan, while a poem was read by their compatriot Lyuba Yakimchuk, who recently fled the country.
“Rain down freedom until we’re all free” sang Legend, who was also accompanied by a gospel choir, as images of those affected by the conflict played out on screens behind him.
At the end of the track, viewers were given the details of a charity helping Ukrainian refugees.
Prior to Legend’s performance Mr Zelensky asked: “What’s more opposite to music?… The silence of ruined cities and killed people.
“The war doesn’t let us choose who survives and who stays in eternal silence,” he added, but spoke of his country defending its freedom “to live, to love, to sound”.
He signed off his video message by saying he hoped his countrymen and women could soon “be free like the people on the Grammy stage”.
Since the conflict began in February, many Ukrainian musicians, producers and DJs have joined the fight against Russia, and also found themselves acting as war reporters and military fundraisers.