Kanye West and Bianca Censori slipped out for a super low-key Christmas Eve date night at “The Nutcracker” ballet in Los Angeles … keeping a tight profile while taking in the entire holiday classic.

An eyewitness tells TMZ … Ye and Bianca stayed for the entire show — Bianca in a fur coat and Kanye in his iconic incognito mask. Our source tells us he did take the mask off during the performance when the lights were down, but made sure to put it back on during intermission and at the end of the show.

We’re told the couple kept a pretty discreet profile throughout the ballet, clearly trying not to draw attention while still soaking in the holiday classic.

Our sources also tell us the fashion-forward, festive duo didn’t dip out early either … and that they watched the entire performance from start to finish.

However … as soon as the final notes hit, we’re told Kanye and Bianca made a quick exit right as the show ended — slipping out before the dancers took their bows through an otherwise closed-off back exit.