"It's fun playing small venues," she says, gazing down at meshed fingers.
It must have felt great, too, raising all that money for Housingworks.
Having appeared briefly lower down the bill, she was summoned back to take over Stevie Wonder's slot after a technical hitch - and her brave conviction stole the show. Her eponymous debut went multi-platinum and won four Grammies, its strummable songs were instantly assimilated into the setlists of buskers the world over. A dedicated fanbase ensured that successive albums sold respectably, but she was happier out of the spotlight, making music in relative privacy.
She doesn't mind, she says, that some people think she's been long retired.
There are disquieting references to hiding from Jesus on the new album.
"I don't know - I'm not sure about anything as far as religion and spirituality go.
"Sure," she looks up, with a beautiful, broad smile, "I wanted to invite not-for-profit organisations linked to local communities to set up tables at the venues and let people know what they're doing." On previous tours Chapman has encouraged voter registration, supported women's shelters and left boxes in the lobby "where people could write anything they wanted.