Sky has announced a brand new, US-content-focused, channel - Sky Atlantic HD which will be the only place to watch the first run of the new Mad Men season in the summer of 2011.

The Guardian is reporting that the subscription-only channel will be available within the £19 Variety package, although at present Sky only offers HD channels to subscribers who pay the £10 HD Pack, and we can't see Sky Atlantic HD being excluded from this set-up.

What it does mean, is that for the first time non-Sky HD subscribers will miss out on the first runs of hit US shows. At present Sky simulcasts its HD programming with SD offerings. It's not clear how far in advance Sky Atlantic HD viewers will get to see shows ahead of SD customers.

Sky Atlantic HD will also host HBO content, following the £150 million deal that was brokered at the end of July.

This means that it will have the UK TV premieres of HBO shows such as Martin Scorsese's drama Boardwalk Empire and The Wire's David Simon's new show, Treme.

The channel will also host British content, with Sky stating it will also become the home for exclusive new UK programming.