How is “sing along” used?

In Come from Away (2021), one line is: “Hey, hey, just sing along Nothing ventured, just prolonged”

Which movie is “sing along” from?

The clip at the top of this page is from Come from Away (2021).

to sing together with sb who is already singing or while a record, radio, or musical instrument is playing

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to sing together with sb who is already singing or while a record, radio, or musical instrument is playing
There's a Messiah sing-along tomorrow. Oh, no!

Definiciones del Oxford Advanced Learner's Dictionary, 9.ª edición

Hey, hey, just sing along Nothing ventured, just prolonged

En 8 películas · n.º 1