For the swanky Tate Americas Foundation artists dinner, our favourite British transplant stuck to her effortless but so-hip-it-hurts style in a simple navy and black babydoll dress. A reminder that the dark shades do work together very nicely indeed.
Alexa kept things low-key with a dishevelled top knot, no jewellery and delicate inky accessories. Less is always more when it comes to the 29-year-old's red-carpet styling.
Other famous faces at the high-brow bash included Sarah Jessica Parker and Anne Hathaway, Alexa's fellow attendees at Monday night's Met Ball. From punk to posh in a matter of hours, we're impressed.
Check out the front-row favourite in our video.