If your fave was given a bunch of instruments could they write and compose an entire album? This doesn’t include producing/engineering obvs, but would they pretty much be able to start writing their album from scratch and send it off to be finalised with only their name having writing/composing credits?
This doesn’t necessarily mean if they have done it before (Speak Now), but it can be determined if say they’ve written half an album before so they have potential to, the songs would have to be decent as well
