I looked for an English source but could not find it.
It was revealed two days ago when the new Oly president was being interviewed by a non-camera related news agency. On the following day, camera a jounalist got confirmation from Oly that the news was correct. It could be that the new president did not know it was kept secret.
Here at roumor sites, lots of discussions are made as to why they kept it secret at the launch and why they disclosed it now. No persuasive comments are found.
Some are wondering if the Sony sensor or other Sony's will be used for future Oly compact system cameras as well. I'm sure that you are one of the people who can know it first. - or you already know it!?
What is interesting for me is that some Sony users want E-system lenses designed by Oly for their NEX system. Another guy says that he hopes Sony will turn from a sensor company into a camera company.
But anyway the info is correct.
Now widespread here. (though among camera lovers' world only)