So Paul McCartney fronts a band featuring the remaining members of Nirvana, makes a decent fist of it and the people who are most surprised are the citizens of Indie Nation, where versatility is despised and people only feel they can properly trust those who've spent years ploughing the narrowest of furrows.
McCartney, whether you like him or not, has worked in more musical idioms over a longer period of time than anyone else and therefore he's the last person about whom you should ever say "but I never realised he could do that".
Every shade of pop and rock and roll, dance music, sound collages, show tunes, classical, film scores, kids songs and "Give Ireland Back To The Irish". He's done the lot. Nobody would claim it's all been uniformly brilliant but he's always been equal to the job and very often he's shown mastery.
Plus, if one living performer could be said to have invented the art of screaming in front of a rock band it was Paul McCartney. He did that with "I'm Down", "She's A Woman", "Helter Skelter" and plenty of other recordings and he did it long before anybody even thought of putting up the discredited polytechnic that is indie rock.
Meanwhile, by contrast, Mick Jagger turned up on Letterman this week to deliver the Top Ten Things He's Learned and proves that it's possible to have spent 50 years at the top of your profession and still trample all over the punch-lines of the writers. This is so bad I have to watch it again and again.