We knew that Ninja Theory was working in a new AAA project using Unreal Engine 4 but we had not seen anything about it until now. Some footage from an unknown project can be seen in a promotional video.

Here you can see some pictures:

ntl1s2n Ninja Theory shows footage from its new project | VGLeaks 2.0

And here you can watch the footage in the promotional video:

NT Website Intro from NinjaTheory on Vimeo.

Thanks to VG247 and Neogaf.