Speaking in an interview with 1Up about the technical specifications of Killzone 3, Hulst accidentally detailed the much demanded feature:

"We found a lot of power after we completed Killzone 2. Just to give you an example on the graphics side: we pulled a level from Killzone 2 into the Killzone 3 engine and it ran at 50 percent. That's how much power we've been able to find," he said.

"You can see it in split-screen co-op. We had to do the double rendering anyway."

Split-screen co-op was rumoured a couple of weeks ago when an errant screenshot leaked. Whether the split-screen will apply to both multiplayer and single-player, we'll have to wait and see. We know a lot of people are going to be pretty stoked by this news though.