BioShock creator and head of 2K's Irrational Games, Ken Levine, has revealed why BioShock Vita was announced at E3 2011, before the game had even entered development - it was because he wanted to help Sony out.

"Look, generally when I announce something... like with BioShock Infinite we had a whole video to show and it was all fully-formed," Levine told Eurogamer.

"Sony was launching this platform and it was important that they had a show of support from people no matter what stage of development they were at.

"Sony has been such a good partner to us, and I'm not just blowing smoke," he added. "Every time we see them they take really good care of us. So they asked me to do that and I said okay, even though that's not what I normally do."

Sadly, despite Levine's eagerness to announce the Vita game, he added that he won't talk about it until he's got something to show - hopefully that will be at E3 in June.

BioShock Infinite is due for release on October 19.