Who: Jason Wu prom dress - but we love her beauty look even more: a slick updo with a side-parting, a soft fuchsia lip colour and a flick of heavy, black eyeliner. (We're also admiring those Lorraine Scwhartz jewels).
Where: Blunt attended the premiere of her new film, The Five Year Engagement, with Jason Segel, 18 April.
Bonus info: Emily completed the green theme with Alice + Olivia pumps.
See more from last night's premiere in the video below: