Mariah Carey is making sure her 55th birthday is "One Sweet Day."
The pop superstar celebrated her 55th birthday — which she famously calls her "anniversary" — on Wednesday. To ring in the festivities, the hitmaker shared a stunning selfie on Instagram in which she looked absolutely glowing and like she was basking in all of the positive b-day vibes.
"Anniversary adventures commence ," Mimi wrote in the caption of the shot of herself.
In the photo, the Songbird Supreme appeared to be relaxing aboard a yacht that was setting sail. She fittingly seemed to channel mermaidcore for the excursion by wearing a tight-fitted, sequined, indigo gown, styling her hair in a curly, flowing ponytail and wearing her eye makeup in a dark purple shade.

Carey looked to be very happy to honor her "anniversary," as she was smiling wide in the photo.
Fans sounded off in the comments with sweet "happy anniversary" wishes, with many noting how she was "giving mermaid butterfly" and looked "beautiful in blue."