Instances of Mickey as an 'actor'...

[Neal]

There are a couple of featurettes/feature films from Disney animation where Mickey isn't really in his true 'universe' but rather like an 'actor' - playing another character.

I'm talking about the 'Mickey and the Beanstalk' segment of "Fun and Fancy Free"

1990's "Mickey's The Prince and the Pauper"

and

2004's "Mickey, Donald, Goofy: The Three Musketeers"

...there's a trend here - Mickey, Donald and Goofy play another role - one in a famous fantasy/myth story.

Are there more instances of this than these three?

[Leviathan]

Although its not based on a specific work, The Brave Little Tailor arguably fits as well.

[Neal]

Yes! That's definitely what I was asking for, thanks! And that's based off of "The Valiant Little Tailor".

[Darking]

All the "Mouse Tales" from Mickey's Mouse Works/House of Mouse have this. I think there are more than these two, but it's all I can remember right now.

"Midsummer Night's Dream"
"Around the World in 80 days"

[Jave]

And don't forget "Mickey's Christmas Carol".

[AdamYJ]

Yes! That's definitely what I was asking for, thanks! And that's based off of "The Valiant Little Tailor".

Yeah, that's what I was going to say before I saw this post.

"The Brave Little Tailor" or "The Valiant Little Tailor" as it is also called, was a traditional German folk tale. One of many collected by brothers Jakob and Wilhelm Grimm in a book that is, possibly, one of the most important and well-known common-property books ever put together.