"Optimist," by Zoe Keating

Zoe Keating is a friend of the show. We've performed live with her around a dozen times, give or take. And on our last tour (Symmetry), Zoe would often play this piece, Optimist, which she wrote for her son Alex when he was negative four months old. Every time, the audience fell into a trance. Those are the moments from the tour I really remember, getting to sit quietly on stage and watch the audience watch Zoe.

If you like this track, check out more from Zoe Keating on iTunes:

• Zoe's 2005 album, One Cello x 16: Natoma
• Zoe's latest album, Into The Trees