Movies with behind-the-scenes scene

[Morsoth]

With the upcoming movie The Making of Psycho (News Link), I was remembering movies that shows making-of-scenes during the movie itself... Obviously, it's often biographical movies!

Gods in Monsters (1998) - Making-of "Frankenstein" (1930)
Dragon: The Bruce Lee Story (1993) - Making of "The Green Hornet" (1966), "Tang shan da xiong" (1971), "Enter the Dragon" (1973)
Return to the Batcave: The Misadventures of Adam and Burt (2003) Making-of "Batman" (1966)

I also think that What's Love Got to Do with It (1993) had a scene like that.
And I'm sure a movie exist about Elvis life with a "behind-the-scene" scene...

Fake Making-of:

Jay and Silent Bob Strike Back (2001) - Making-of the fake "Scream 4"

I'm sure I forgot a lot of movies. If you know movies like that, please post them here!