Margot Robbie Only One on Pink Theme for 'Barbie' Press Shoot

Margot Robbie is about to play Barbie on the big screen -- and in the lead-up to that, she's also the only one who apparently knows there's a theme to this ... color-wise, we mean.

The actress showed up to a press shoot Sunday in Beverly Hills with a bunch of her costars from the flick -- including Ryan Gosling, who's playing Ken. They all got together to pose for shots and to talk to journalists ... but MR stood out like a sore thumb, in a good way.

Take a gander ... she's quite literally the sole person rocking pink, and the juxtaposition is jarring. Everyone else is in brown/beige/grey -- as if they were there to promote "Dune 2" and not THE "Barbie" movie ... which is all about girly-girl vibes and vibrant shades/tones.

As we said, Margot did her job and served as a good soldier for the promo ... as she has been for the past several months now. She certainly knows how to telegraph Barbie.

A lot of people say she was born for this role ... and by the way she's oozing Barbie-core of late, that's probably accurate. Plus, this flick stands to be a big bounce-back for her in terms of projected box office numbers ... it's one of the most highly-anticipated films of the year.

In light of a couple of flops she was a part of last year, Margot could use a big opening weekend -- and considering all the fanfare and chatter online ... it's definitely got a chance.

Of course, she and the rest of the "Barbie" crew will have stiff competition that weekend ... Christopher Nolan's new blockbuster, "Oppenheimer," is coming out the same day -- and it too has a very starry cast, albeit a completely different tone.