He mentioned it on Chatterbox.
Also, the original, Manley Pope is blonde:
Vs.
http://www.tdf.org/PlaybyPlayOnline/pp9305/elvis.png ________________
"To begin with, the book by Joe DiPietro (I Love You, You’re Perfect, Now Change, The Thing About Men) is Shakespeare compared to the book of Mamma Mia!. No, really, it literally is because the main premise, in which a woman poses as a man to win the love of a man, is taken from Shakespeare’s Twelfth Night."
http://www.talkinbroadway.com/regional/chicago/ch51.html Except, I didn't like the part where he said, "Most of the transitions between DiPietro’s book scenes and the Elvis songs in act one are as abrupt and awkward as they are in Mamma Mia!."
I mean, it was abrupt - but it was done so well...and made it so funny.