Olympus and Panasonic have announced a new, mirrorless format lens based on, and compatibile with, the Four Thirds standard.
The "Micro Four Thirds" system uses the same 18 x 13.5mm sensor size but allows the camera to be around 50% slimmer by removing the mirror box and optical viewfinder. Instead, you'll have to use the LCD screen to frame your subjects.
A smaller diameter lens mount of around 6mm also means that lenses will be smaller, however existing Four Thirds lenses will still be able to be used on Micro Four Thirds cameras with the use of an adapter.
Neither company has made any product announcements, but have said that they will work together to jointly develop relevant technologies and devices for both the Four Thirds and the Micros Four Thirds System standards.
Expect some news closer to Photokina.