Miley Cyrus and Kaitlynn Carter Out Together in New York City

Miley Cyrus is keeping Kaitlynn Carter right by her side ... and they're stepping up their fashion game since their getaway in Italy.

The singer stepped out Tuesday night with her rumored girlfriend for a night on the town in New York City ... dressed in all-black, sleek matching outfits.

Miley's in the Big Apple for New York Fashion Week ... and after her tribute performance at the David Koch Center, she went back to The Greenwich Hotel to grab Kaitlynn for what looks like a date night.

Miley and Kaitlynn have been pretty much inseparable since Miley announced a split from her estranged husband, Liam Hemsworth.

As we reported ... Miley and Kaitlynn went on a lunch date in Los Angeles over the Labor Day weekend, and Miley's mom, Tish, tagged along.

They've each had solo outings, but Miley and Kaitlynn have pretty much been tied at the hip since returning to the States from their Italian vacay.

We broke the stories ... Liam filed for divorce from Miley last month, and she's keeping the pets they owned together when everything's ironed out. So far, the split has been pretty nasty.

Meanwhile, Kaitlynn's going through a breakup of her own with Brody Jenner.