What is Mother Gothel's Accent?

What is the accent of Mother Gothel in the movie Tangled?

In an interview with the voice actor (see here), she has a pretty neutral American accent (GenAm + father-bother + caught/cot, from what I tell), but she switches to an almost mid-Atlantic pronunciation for the character. Is this a mid-Atlantic accent? I think I've heard this type of pronunciation among storytellers in movies: It gives them a fanciful, but not posh, sound.

Here's an example of just the (as of now) unidentified accent, song.

Update: In contrast to the mid-Atlantic accent, Mother Gothel uses [iɐ] and [eɐ ~ ɛɐ], not [ɪə] nor [ɛə].

It sounds like a standard stage singer's accent to me. One thing to remember is that opera and stage singers must enunciate words differently from "normal people" in order to both "project" and be understandable to the audience. The accent isn't necessarily in emulation of anything so much as a necessary modification of the voice to be heard and understood in a particular environment -- like a sailor yelling "Ahoy!" or a goatherd yodeling. (Of course, since this is a studio production the voice is not necessary, but it's the one that the actress and producers presumably wanted.)

(I don't pretend to understand this, but it gets into the gory details fairly rapidly. Basically, the singer attempts to "form" the voice to project specific frequencies in an enhanced fashion.)