For weeks now, there have been rumors pointing to a Gran Turismo 6 announcement coming. The rumors of a Gran Turismo 6 announcement have been leaked mostly through retailer sites via listings. Next week is going to be a huge one, because next week is the 15th Anniversary of the Gran Turismo series and Sony has an event planned just for it.
Today Sony's Europe branch has been sending out invites to people for the 15th Anniversary of Gran Turismo event. At the event, Sony is going to celebrate the 15th Anniversary and even plans to reveal the future of the franchise. The activities can be kept track of on the PlayStation Blog, and can be seen at gran-turismo.com and on twitter (#15YearsOfGT). A teaser trailer has also been released by the company. The event will take place on May 15, 2013.
Source: PS Blog.