The rapper/producer hit the town in L.A. Wednesday night with BC in town -- with the both of them attending Ty Dolla $ign's birthday bash at the Nice Guy in WeHo ... and of course, everyone was paying attention to what they were wearing, especially Bianca.

As you can see, she was rocking a unique getup ... some kind of dress that had a big slit down the middle and which exposed some cleavage and a bit of her stomach too.

The dress itself is certainly its own kind of style -- but frankly, we've seen the all-white motif with Ye before ... notably, he and KK used to sport that look low-key all the time while they were together in the 2010s. There's countless pics of them wearing something similar.

Even when it comes the slit-down-the-middle design for the white dress ... Kim herself has been there and done that -- and while we hate to compare, ya kinda have to here.

Bianca has, of late, been getting called the "it" girl for fashion ... but in this case, it would appear she's actually channeling Kim -- or, as some might put it, perhaps copying her.

Funny enough ... Kim has also been accused (albeit in jest, we think) of ripping Bianca's aesthetic lately -- namely, showing a lot of skin and flaunting assets in no uncertain terms.

Here, though, it would appear BC is doing her best KK ... and it might be Kanye's doing.

Fact is, Kanye famously styled Kim for years ... something she (and he) got praised for a lot in their heyday as an A-list couple. Before Ye came along, Kim wasn't particularly known for her fashion sensibilities -- but in the Kanye era, she was a bit of an icon in that regard.

Now that the dude is with Bianca ... we've seen her wearing tons of crazy s***, and while it might be a lot for most -- some have actually given her (and Ye) kudos for the daring looks.