So can Britney, Madonna and Girls Aloud actually sing?
They all sound more-or-less the same, but beneath all the studio trickery, can our favourite stars really sing?
Sound engineer Ciaran Byrne reckons 'yes'. "Ultimately, you can't fix everything with Auto-Tunes," he says. "If someone hadn't a note in their head, no amount of studio trickery would make them sound good. So the likes of Britney Spears can all sing to some extent; no record company will invest that much in someone who just looks the part."
Broadcaster Nadine O'Regan says: "Nadine Coyle can sing beautifully. And I find Girls Aloud impressive because they often sing live. You might say, 'oh big deal', isn't that what singers are supposed to do? But when you're doing as much promotional work as they do, it'd be easier to lip-synch. Britney can sing, too -- but singing is the last thing she does these days."
And journalist Michael Hann puts it all in perspective by saying: "Does it matter? The records sound great -- that's what counts."