The animation sequence will be hand-drawn but the movie is not for Disney.
Brad Bird wrote:The next thing I'm doing, if I have any say so in the matter—I can't pay for it myself—is a live-action film, a musical that has about 20 minutes of animation, largely that will be hand-drawn. I also have a couple of ideas for feature animation that I also want to do hand-drawn just because I miss it so much. I don't prefer it; there are definite advantages to CG. It's an amazing tool, obviously. I've enjoyed using that tool but there's a certain itch that only hand-drawn scratches and I'm itchy right now to do that.
Source:
https://maltinonmovies.libsyn.com/brad-bird
Q: Well, just the past few days you've started talking about what your next project might be. Are there any details you are able to share with us about that project?
Brad Bird: Yeah, it's a project that I've been wanting to make for a long time. In fact, it predates Iron Giant in terms of the idea that I've had and I've wanted to pursue. I actually pitched it to a movie studio a long time ago. So, I'm returning to it and I have a lot of changes for the story that I want to do. It's a live-action musical but it has probably 20 minutes or so of animation in it. But it's not the way people are thinking about it. People are thinking about it something like Mary Poppins but it's not. It's a little more modern than that in its style. I think it will be really exciting and really fun.
Q: Do you have any details on the style of animation that you hope to use in the project?
Brad Bird: Certainly a large part of it will be hand-drawn. So, that's a little different than the CG that I've been doing with Pixar.
Q: Is this a Disney project or is it set up at another studio? Are you able to share that?
Brad Bird: No, it's actually at another studio. It was originally at TriStar which makes it at Sony. But you know, it's something that I'm interested making and when I flesh it out we'll see if people will have the gumption to [embrace] something new and different 'cause I think it is something like that. To me it is exactly something that I would love to see in a movie theater.
Q: Do you hope to pair with Michael Giacchino again especially since it's a musical?
Brad Bird: Oh, absolutely. Yes, yes. We've been discussing it for a while so...It's a chance for us both to roll up our sleeves and do something that scares us a little bit in a really good way.
Source:
https://www.nextbestpicture.com/latest/ ... -brad-bird
In a December 2004 interview for Starlog Magazine, he mentioned in passing the project in question.
Among those projects that just didn’t fly were the SF detective yam Ray Gunn and The Spirit, an animated version of Will Eisner’s comics crime-fighter. “There was also a live-action movie called ‘Brothers in Crime’ Bird reveals, “and then I was involved for a very short time with a film called ‘Little Monsters’, which could have been cool if it had been done the way that I wanted to do it, but when it became clear that they wanted to do it really cheaply, I bailed. I had another project that got stuck at TriStar that I believe could have been a great movie. In fact, I still believe each one of them could have been great. And they would get cancelled for the most mundane of reasons. The guy who was my executive would get fired, and then the next executive wouldn’t want anything that the previous exec had done; or a film that was vaguely like [my idea], with one similar element, would tank at the box office and therefore — there’s no vision.”
Source:
https://archive.org/details/starlog_mag ... G/page/n45