I thought the accent was usually referred to as 'Mid-Atlantic' but maybe that's a different one again.

Anyhow, isn't history littered with singers singing in accents that weren't necessarily their own. The middle of the last century for example had more than a few British singers use 'proper' enunciation or 'BBC English' or whatever you like to call it that I doubt reflected the speech they grew up with. But at least it was still English you'll probably say.