So, here's the deal ... "Barbie" is a WB movie, and the film's official U.S. Twitter account replied to some fan-created fun art of Margot Robbie (as Barbie) riding Cillian Murphy's shoulder (as Oppenheimer) with an explosion and fire in the background.

It's a Barbenheimer gag obviously, and seemingly innocent on its own ... that is, until the U.S. "Barbie" Twitter account chimed in with the comment, "It's going to be a summer to remember," adding some cutesy emojis to boot.

That didn't sit well with folks in WB's Japanese arm -- the official Japanese "Barbie" Twitter account blasted its parent company for co-signing on the joking atomic bomb imagery.

It wrote, "We consider it extremely regrettable that the official account of the American headquarters for the movie ‘Barbie’ reacted to the social media postings of ‘Barbenheimer’ fans. We take this situation very seriously. We are asking the U.S. headquarters to take appropriate action. We apologize to those who were offended by this series of inconsiderate reactions. Warner Bros Japan."

Yep, that's a big yikes. 😬

So, in response to that public call-out, Warner issued its mea culpa -- "Warner Brothers regrets its recent insensitive social media engagement. The studio offers a sincere apology."

BTW, Twitter/X itself didn't find the imagery very amusing, because the company actually slapped a fact check Twitter note underneath -- mentioning the hundreds of thousands of Japanese deaths that resulted from the U.S.'s decision to drop bombs during WWII.

There's been a lot of chatter about "Oppenheimer" and its handling of the depiction of the Hiroshima/Nagasaki bombings -- namely, the fact the movie doesn't show it whatsoever. Some feel like the film glossed over the impact of the bombings ... and have found it insensitive to the countless lives lost in Japan.

That appears to be the position of Japan as a nation, too ... because it has yet to set a release date for the film within its borders.