As Grand Theft Auto IV finally makes an appearance in Japan, attention in the west is turning to the first of two downloadable content packs for the game, which is due to launch exclusively on Xbox 360 in the next few months.

Scheduled to arrive before the end of January, the content of the expansion packs has been kept close to Rockstar's chest, but in an interview with US entertainment mag Variety, co-founder Dan Houser has revealed that perhaps gamers won't have to long to wait.

“...we don’t know a date. We hope to be announcing that in the next few weeks. We're still figuring out a few things. We're more focused on quality than dates, always have been. But the development is going really good. It's shaping up to be something we're very proud of. That was our goal.”

Houser also reaffirmed that as the expansions were a new experience for Rockstar, one of the issues has been to keep the expectations of gamers firmly on the ground: “We want to give people a rough idea so their expectations are roughly in line. We don't want them to imagine it's this enormous thing that it can never be...Doing a big digital launch is something we've never done before. It's virgin territory, but at the same time, we feel very exposed because there's no case history. No one ever came out with major DLC for a major game like this before.”

He added, “It's new territory for everybody. We're making it up a little bit as we go along. That's always fun, but it makes you nervous.”  The Creative VP at Rockstar also confirmed that the difference between the US and European release of the downloadable content could be just a few days.