I feel it’s imperative you all know what Lady Gaga is wearing to attend the London premiere of A Star Is Born tonight. The pop singer-slash-actress-slash-meat dress connoisseur wore an Alexander McQueen gown—not just any gown, but a ruffled, gilded one from the brand’s Fall 2013 collection that’s giving off major Shakespearean vibes. A midsummer-but-really-early-fall…