What? The actress attended a press launch for series three of the TV show and perhaps it's because we're used to seeing Froggatt dressed as a maid, but her chic sixties-inspired style well and truly impressed us. The monochrome mini? Tick. Cute shoulder bag? Tick. Bouffant plait? We've never tried it, but it looks good.
Where? New York, 12 December
Verdict? Top marks to Joanne's not too-glitzy but oh-so-sleek party style. Let us know what you think of her look and see more sixties style below: