Mario Kart series producer Hideki Konno has revealed Nintendo saw finishing work on Mario Kart 7 as an "act of emergency", according to a new Japanese Iwata Asks article (via Eurogamer).

Konno reveals the game started development with just eight staff attached, but that once team members were peeled off to work on Nintendogs + Cats the team needed external help, with Retro Studios stepping in to help put things together.

Retro set to work on bringing the game's 16 classic courses up to speed, leaving the rest of game development to Nintendo's internal team.

We'll see how the game stacks up when our review goes live next week.