Songwriter Cameos on Cast Recordings

There've been a few times when I've listened to a musical's cast recording where I noticed the voice of the songwriter appears on it for a brief second. I think it's a fun Easter Egg, and enjoy when I hear them. A couple I've noticed:

1) William Finn plays the umpire on "The Baseball Game" in Falsettos (revival cast recording)

2) David Yazbek sings on the diagetic record within "Time Stood Still" in Women on the Verge of a Nervous Breakdown

3) Jason Robert Brown as the announcer on "When You Say Vegas" in Honeymoon in Vegas (I'm not 100% sure it's him, but it does sound a lot like his speaking voice.

What are a couple you've noticed?

Mel Brooks sings the line "Don't be stupid, be a smarty, come and join the Nazi Party" during "Springtime for Hitler." (They also used his voice for that line in the actual show as well)

The Waitress one is an unusual example, because while Bareilles appears at first to be just a pre-recorded chorus vocal, as the show goes on it's heavily implied that she's actually the remembered voice of Jenna's mom. So Bareilles plays a pre-recorded but significant character in the piece... even when she's also in the show, playing her own daughter.

AEA AGMA SM said: "Mel Brooks sings the line "Don't be stupid, be a smarty, come and join the Nazi Party" during "Springtime for Hitler." (They also used his voice for that line in the actual show as well)"

That’s a carryover from the original film as well. Mel Brooks dubbed it because he didn’t like the way the actor delivered the line.

Other fun fact about that scene: The Producers was filmed on a shoestring budget, and they couldn’t afford to film in a theatre with a pit, so the “conductor” is sitting on a crate at the bottom of the frame.