Does the US accent really override UK accent worldwide now?

Singing in another accent in popular music seems to be a common occurence. How many rock groups--both U.S. and British--sing with pseudo-black accents, in imitation (conscious or otherwise) of R&B singers. (Such as: I heard of some black musicians discussing what part of Louisiana the group Creedence Clearwater Revival was from--and surprised that they were a bunch of white kids from California.)

I'm still amazed when I turn on a show like American Idol, and the majority of contestants are doing either a black or southern/country accent, regardless of where they're from.

It's undeniable that most British "singers" of popular cuture do adopt an American style accent which is far, far removed from their normal speaking accent. There's no doubt about that - it's everything to do with international appeal - not to mention sheer commericalism.

Singers outside the pop cutlure sphere are a different matter altogether, though.......no British singer would ever dream of using an American accent when standing in front of a huge audience at the Royal Albert Hall in London singing something like "O, Green Hills of Somerset" or "Sweet Lass of Richmond Hill"!

Cher sounds Californian in interviews, but she sings with a BackEast accent.
She pronounces ''long, song, dawn,on '' with /A/ in interviews, but with /Q/ when she sings.