The Barbican are showing a preview screening of Broken English, a film about Marianne Faithfull. I know nothing about the film, looks like a biopic. Anyway, relevant here because it's accompanied by a (short) live performance of artists performing Faithfull's songs, and featuring Jarvis, and several other lovely people. As it's listed as 40 minutes, I would guess they're doing one song each - but who knows, there may be collaborations.
Can't go myself, too busy (and seeing Mr Webber the night before in York), but I plan to see the film.