Austin Gorg, the art director of Damien Chazelle’s 2016 hit, "La La Land," hasn't really noticed the comparisons himself ... but he tells TMZ any similarities are no big deal 'cause filmmaking often involves borrowing a bit of inspiration from other people's work.

Austin reckons the Todd Phillips-directed 'Joker 2' drawing comparisons to Ryan Gosling and Emma Stone's flick is likely just a case of both films tapping into well-worn cinematic tropes explored by many movies -- as he points out, "La La Land" was essentially a love letter to classic films, even using sets from old-school musicals.

As for the scene of Joaquin Phoenix's Arthur Fleck and Lady Gaga's Harley Quinn dancing in the moonlight, which mirrors a similar moment with Stone and Gosling in "La La Land," he says it's nothing new -- it's just basic movie magic to enchant audiences.

Austin says the same goes for the spotlight on Joaquin playing at the piano ... saying it's just pure stagecraft, as it was when Gosling acted out a similar shot 8 years earlier.

He summarizes, "The comparisons probably say more about our online culture than any meaningful critique of the film. That said, I'm happy that people are engaged. It means movies are still at the core of our culture."

It's no secret the art direction and cinematography were key players in driving fanfare and award-season buzz in both "La La Land" and the first 'Joker' film.