In November, long-running British cop show 'The Bill' will team up with a German police series, 'SOKO Leipzig', for a special marking the 25th anniversary of 'The Bill'. It will be filmed both in Britain and in Germany with both production companies involved sharing the footage. The German version will be somewhat different from the British version as ZDF will take the footage to present their own version of the story. (I'm not sure if this means we'll just have a different viewpoint or that it should be relegated to an alternate dimension because of any possible discrepancies between the two.)
Hopefully I'll be able to track down at least the British version of the special crossover. Barring that, there will probably be plenty of pictures to be found on the web as the date of the broadcast draws closer.
(Thanks to Medium Rob for the news link!)