I wasn't sure at first, but I am now certain I own the dress Birdy wears while she plays the piano in her 'Skinny Love' video.

It's from Topshop, however it isn't currently on the website, so I can't confirm the price of it yet.
I think it was about £48, and I used my student card to get a 10% discount.

It's more than worth the price, I've worn it during the day, to a gig, to go out in and for formal events.

If you haven't listened to the song yet I strongly recommend you do, she's 14 and extremely talented: http://www.youtube.com/watch?v=aNzCDt2eidg