I believe the music is from the Cocteau Twins called "Pandora" but it's a remixed version by Ross Gregory/Aardvark Sounds. I think it was specially made for the advert so sadly this beautiful piece of music won't be available :(
http://www.youtube.com/watch?v3Sv4bdD-wEU
A couple walking in a street in the night elegantly dressed. Diamonds and flowers flowing in the womans dress in gold.