Emma Corrin has revealed that she wears a chest binder made by a transgender-owned company and uses the pronouns she/they.
The 25-year-old actress shared a set of black and white pictures on Instagram of herself wearing boxing wrap, a fabric binding used by boxers. Her account also displays her pronouns as she/they.
Chest binding is common among people who want to give the appearance of a flatter or less feminine chest.
Corrin said in her post that before she purchased her first binder, she had used "boxing wrap".
She added that she now used binders from gc2b, which describes itself as "the very first gender-affirming apparel company that is trans-owned and operated".
Corrin, who won a Golden Globe for her portrayal of Diana, Princess of Wales in The Crown, did not say why she had chosen to wear one.
"Some time before I bought my first binder, messing around with [David-Simon Dayan]," she wrote. "We used boxing wrap, thanks for capturing this with me, very intimate, very new, very cool. It's all a journey right. Lots of twists and turns and change and that's ok! Embrace it."
Mr Dayan, a US-born photographer, shared Corrin's post with the caption "love you". Her post has since been liked more than 150,000 times.
Commenting on her post, fans and celebrities showed their support. Singer Paloma Faith wrote "Beautiful pictures", while artist Arlo Parks said "Angelic".
One fan wrote: "Amazing! I just bought my first binder. Journey on."
Another said: "Thank you for stating which binder you use. My child recently came out to me and told me they wanted one. I'd no clue where to look or who to ask."
In April, Corrin shared a picture on her account wearing a wedding dress for a Pop magazine feature captioned: "ur fave queer bride."
The LGBT Foundation, a Manchester-based charity, advises: "Binding incorrectly can do damage to your body, and we would recommend avoiding using alternative ways to restrict your chest". These include bandages, duct tape or sports tape.
It also recommends not binding for more than eight hours at a time and to take breaks.
Corrin's management was contacted for comment.
