Now the virginity of Mary was hidden from the prince of this world, as was also her offspring, and the death of the Lord; three mysteries of renown, which were wrought in silence by God. How, then, was He manifested to the world? A star shone forth in heaven above all the other stars, the light of Which was inexpressible, while its novelty struck men with astonishment. And all the rest of the stars, with the sun and moon, formed a chorus to this star, and its light was exceedingly great above them all. And there was agitation felt as to whence this new spectacle came, so unlike to everything else [in the heavens]. Everywhere magic crumbled away before it; the spells of sorcery were all broken, and superstition received its death blow. The age-old empire of evil was overthrown, for God was now appearing in human form to bring a new order, even life without end.
I’m told by a premier expert on Origen that he expressed much the same thing. So we can see that the idea existed a good 200 years before Athanasius, though he wrote as if he also had personal experience with it.