The story
From moon + struck (adjective), possibly coined by the English poet and polemicist John Milton (1608–1674): see the quotation. Compare Medieval Greek σεληνόβλητος (selēnóblētos), σεληνόπληκτος (selēnóplēktos), German mondsüchtig, and German Low German maansüchtig, which also refer to being struck by the moon.
Etymology from Wiktionary, CC BY-SA 4.0.