How is “know what you're talking about” used?

In Luca (2021), one line is: “You don't know what you're talking about!”

Which movie is “know what you're talking about” from?

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

to have knowledge about sth from your own experience; to say you do not understand what someone is referring to, often as a denial or brush-off

informal · Heard in 76 moviesPlay Idioms

Oxford55% of films
to have knowledge about sth from your own experience
Editorial45% of films
to say you do not understand what someone is referring to, often as a denial or brush-off

Definitions from the Oxford Advanced Learner's Dictionary, 9th edition

You don't know what you're talking about!

Said in 8 films · #1