The duo performed a rendition of 'Your Song' as part of the Station Sessions, as well as switching on their Christmas lights.
Watch the performance and interview exclusively below:
Discussing their musical interests outside of the classical genre, Jonathan revealed: "I've found interest in grindcore recently. Not a lot of people know what it is, but if they do, they'll be a bit weirded out.
Charlotte added: "I recently listened to a folk song and that for me is branching out! I usually listen to a lot of musical theatre."
The pair also announced plans for a full UK tour next summer, adding: "We've got a tour in 2013 next June. We're going up and down the UK performing our album."
Jonathan & Charlotte will be performing a concert as well as turning on Trafalgar Square's Christmas lights on Saturday, December 8.
The show has been organised by Boris Johnson to recognise the contribution of the Capital's volunteers to the Olympic Games this summer.