Surprising absolutely no one, Sega announced a new addition to its ever-growing library of Olympic crossover games. Mario & Sonic at the London 2012 Olympic Games is coming to the Nintendo Wii and 3DS. Oddly, the announcement doesn't include a regular DS version. Release dates will be announced later this year.

The Wii version will bring back games from former summer Olympics titles, like aquatics and table tennis, along with new additions like soccer and equestrian events. It will also add "Dream Events" set in Mario and Sonic locales. The 3DS version promises 50 Olympic events. Both versions include both single- and multiplayer modes.

As usual, the game is being developed by Sega Japan, and published by Sega, with Nintendo no doubt sharing some generous licensing fees for its characters. Sega brags that the combined sales from previous incarnations tops 19 million copies, so it's really no wonder they've opted to make another.

"Mario and Sonic have had a phenomenally successful partnership and we are extremely proud to be able to recreate this once again with Nintendo and ISM for the London 2012 Olympic Games," said Sega chairman Naoya Tsurumi in the announcement. "It is truly exciting to be in the position to develop interactive entertainment software titles based on the Olympic Games, and for Sonic and Mario to once again be a part of this historic event."

We got a hint of this game last week, when logos leaked for both it and Sonic Generations. When the latter was announced a few days ago, it seemed like only a matter of time before Sega confirmed Mario and Sonic's trip to merry old England.