No, Celebi or any other Legendary Pokemon can't have an egg.
in japan version einstine
you can not get him in the game
you cant
Celebi isn't obtainable in Sapphire Version. You can only get it through a promotional event.
The only game you can currently get Celebi in is Emerald version (until the Celebi event happens for HG/SS).
The only way to catch Celebi in Pokemon FireRed Version was to get the special Pokemon from a event. The only other way would be to cheat using an action replay device with a code.
Celebi does not appear in the gold or silver games, however he does appear in Pokemon crystal.
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The only way to obtain Celebi in Pokemon Diamond is to transfer it from GBA via Pal Park.
Celebi is a legendary Pokemon that was only available through a Nintendo event. It is not found in the wild unless the player has a GS ball in Pokemon Crystal.
I don't think you can catch celebi at all in fire red. There is one way though bring your gameboy/ds with a wireless adapter to a Pokemon convention to get celebi.