Prequel to The Impossible Astronaut, via the BBC Doctor Who site.
The clip is also available on the BBC America website (only viewable inside the US)
You can also watch a teaser for the video on the BBC website.
The Doctor Who website reports that they will be "revealing the latest iconic image for the new series at approximately one minute past midnight on Saturday morning", which will be available to download as a wallpaper. They also report that several exclusive videos featuring the cast and crew discussing the new adventures of the TARDIS crew will be appearing on-site in the lead-up to Easter's broadcast of The Impossible Astronaut.