Emma Dumont's making a major revelation ... revealing they're non-binary -- and, their friends and family are calling them by a new name.
The "Oppenheimer" star changed their pronouns and name on their Instagram bio recently ... writing they now go by "they/them" pronouns instead of "she/her."
We reached out to a rep for Dumont who tells TMZ ..."They identify as a trans masculine non-binary person. Their work name is still going to be Emma Dumont, but they will go by Nick with friends and family."
Dumont's career has taken off in recent years ... with Emma scoring major roles in Paul Thomas Anderson's "Licorice Pizza" and Marvel's TV series "The Gifted."
They captured international attention last year while starring as Robert Oppenheimer's sister-in-law Jackie in the blockbuster hit "Oppenheimer."
Emma's posted multiple times in recent weeks ... dropping selfies and other pics in various posts -- though never really addressing their recent coming out.
Their next flick "The New Me" doesn't have a release date yet ... though clearly, it will still be credited under "Emma Dumont."