Complex sentence: The advert is already said to be one of the most powerful of the year so far; on May 1 2010, a new version of the advert aired; which shows more of the song cover.
Split into simpler sentences: The advert is already said to be one of the most powerful of the year so far. On 1 May 2010, a new version of the advert aired; which shows more of the song cover.