The living Beatles, and the wives of the dead ones, are full "creative partners" in the development of the new Rock Band game, according to Harmonix.
Speaking to Crispy Gamer lead designer Chris Foster said, "The shareholders, as we call them - Paul and Ringo, Olivia and Yoko - were really creative partners throughout the project.
"They were involved in picking and approving the song list, the venues we went into. With the dreamscapes, they saw storyboards of all of the material, and gave feedback on whether or not they felt like those interpretations supported the songs in the way they wanted."
The fab two and the other two also cast their eyes over the character designs and animations. "With Rock Band, you've got these avatars that are, you know, anyone, so it's pretty easy for you to believe in them. But when you know who the Beatles are, and you know the joy in their faces when they play, you have to capture that on-screen; you have to be true to that, and they were really good about keeping the standard high."
That applied to the standard of playing, too: "I think Sir Paul McCartney heckled our project lead's bass-playing when he saw one of the game demos," said Foster.
"So yeah," yeah, yeah, yeah, "They were involved. I'm not going to put words in their mouth, but seeing all four of them at the Microsoft press event is about as validating as everything. They don't get together for almost anything... It has to be something important, something they believe in."
The Beatles: Rock Band is due for a release on PS3, Xbox 360 and Wii on 9th September. You can find out all the business via the gamepage.