Their shared aims include raising awareness of HD through advertising and events, and offering customers savings when they buy a Sony HD TV set and a Sky HD Box together.
The Sky HD box will be necessary to view the package of HD channels ranging from sports and movies to arts. Sky is to launch in the UK and Ireland in the first half of next year.
The agreement was unveiled by Sky's chief executive James Murdoch and Sony's chief executive and chairman Sir Howard Stringer, who said it would help HD to realise its full potential.
"Until today we have laboured under a Catch 22. If the industry didn't produce and broadcast in HD, the consumer would be reluctant to purchase HD televisions or equipment," Stringer said.
Sky expects to sell 2m HD sets in 2006, compared with 700,000 this year.
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