Where is it mentioned that Humpty Dumpty was an egg?

Grace.'s picture

Where is it mentioned that Humpty Dumpty was an egg?

Not quite sure how I'm going to carry a dinosaur costume on the bus tomorrow...but I shall manage.
Perhaps I'll make friends with an elderly woman, then when she isn't looking I will steal that chain that is connected to her reading glasses.

Oh, I'm just too diabolical for my own good :)