The actress wore the unusual, embellished frock to the London screening of the romantic drama co-starring Michael Sheen on Wednesday night (15 April).
It's based on the novel by Thomas Hardy about a female farm owner, played by Carey, who attracts the attentions of three very different men: a farmer, a military man and a mature bachelor.
We can see it on screens from 1 May.
Carey's been a very busy lady lately as she has another movie coming out soon, Suffragette, about the women's right movement.
Co-starring Meryl Streep and Helena Bonham-Carter, it's made movie history before its release by being the first film ever to shoot on location at the Houses of Parliament.
It's in cinemas 30 October.