The Beatles: Rock Band will feature "stuff that has never been heard, never been released," according to George Harrison's son.
Dhani Harrison revealed the news, although he didn't go into any more details, in an interview with Billboard.com.
Harrison also said that the game, which was recently dated for September 9, has been being worked on for a couple of years now.
"I took the project to Apple and sort of convinced everybody to have a presentation," he said. "My job description is...being enthusiastic. We've been working on it for the past two years. This is the first one that is going to be totally, historically accurate. It's been a real headache, but it's been the most enjoyable work I've done in my life."