The 'Unconditionally' singer ditched her trademark technicolour palette for a pared-down look for a night out at swish Mayfair restaurant 34 on Monday.
Instead of her trademark bold lips, Katy opted for a 90s-inspired, brown-toned hue and bronze eyeshadow - a look that reminded us of none other that our favourite 90s beauty crush, Rachel from Friends!
And Katy looked classy in a chic black knee-length sweater dress with pearl embroidery across the shoulders, by Alexander McQueen, paired with simple black opaque tights and patent Mary-Janes.
But don't worry, Katy hasn't gone all sensible on us. The 29-year-old star performed at the Capital FM Jingle Bell Ball on Saturday, where she rocked up the red carpet in a floor-length pink leopard-print thigh-split dress and bright pink lips.
Watch Katy's gothic glamour video for 'Unconditionally' below: