The actress/singer hit the red carpet Sunday at the Fairmont Century Plaza Hotel in L.A., where she was one of the clear standouts of the night in terms of fashion ... wearing an elegant black dress that appears to be from Vera Wang's Spring 2023 collection.

Of course, while she looked great ... what really turned heads was the fact that her gown was see-through, especially upstairs -- where she didn't seem to be wearing a bra.

There were other somewhat revealing cutouts in the dress -- around the pelvis area -- that made it a total stunner ... and Janelle pulled it off with style. She's naturally a knockout, but a lot of people were kinda shocked she went out there like this ... showing off the bod!

Eventually, she accepted her award for the night -- which was meant to honor artists who offer up representation and authenticity in their roles and performances and work ... and Janelle does both in film and in her music. She acknowledged as much in her speech.

JM identified her pronouns (she/her, they/them) ... and made a point to shout out any LGBT kids at home who might live with families who don't accept them. She said, "I see you."