BioWare has confirmed Mass Effect: Jacob's Story for iPhone and iPod Touch, after a focus group tester broke NDA to leak the project last month.

The game will not be a prequel to Mass Effect 2, however, but a side-story about one of the characters in it.

"Yes, this is not a hoax or fake story. BioWare is making a game for the iPhone and iPod Touch based in the Mass Effect universe," writes BioWare's community manager Chris Priestly on the official forum.

"The story of the game is not a 'bridging' story between Mass Effect 1 and Mass Effect 2. It is a cool little side-story about one of the upcoming Mass Effect 2 characters. It is not 'required reading' to enjoy the core trilogy, but a fun optional 'extra' game."

Jacob's Story - a blend of top-down arcade shooter combat and graphic novel-style story sequences - will be developed by a separate team within BioWare that has nothing to do with the hold-up of any new Mass Effect DLC.

Other details on the project are scarce. Priestly promises the wraps will be off sometime during this month or June, so E3 is probably a safe bet.

That, promises BioWare, will be when we hear more about Mass Effect 2, which is scheduled for launch on PC and Xbox 360 next year. Co-op and use of saved games from ME1 are among the features rumoured for the sequel so far. Mass Effect 1 hero Commander Shepard may also not be as "killed in action" as the first teaser trailer for Mass Effect 2 suggests, either.

"I've heard some rumours that Commander Shepard is dead," writes executive producer Casey Hudson on the Mass Effect 2 IGN blog.

"Better not be. We had a lot of big plans made, so if someone's gone and killed Shepard then things are going to take an unexpected turn..."