Perhaps it comes as no surprise that she is very strong even when detransformed, and may be it wasn't supposed to be found out this way.
She walked in to the waiting room with her hair piled up into a bun, her eyes bright though not super enthused about a regular checkup at the doctor's office, and she carried herself well, with a certain assured confidence that must have taken years of being Ladybug to fully establish.
Marinette Dupain-Cheng was a new patient to this particular office, and naturally she got the newest doctor, a young man that was good at what he done, and so when she followed the nurse and sat down after quickly answering questions and had to wait for the doctor to arrive in the room and make sure that she was perfectly fine.
She began by counting the designs on the wall and ceiling as sometimes the wait could be excruciatingly long though she counted herself lucky when she'd only managed to count six of the thirteen or so decorations on the wall as he walked in though he looked more than a little familiar to her, "Adrien Agreste?"
He smiled back at her, but didn't really offer much else other than the basic questions before he'd have to check to make sure that she was indeed fine.
When he pressed the stethoscope to her stomach and told her to breathe deeply, she realized that he was surprised briefly by how muscular she was.
It was only when he'd slipped up later on and called her by 'Ladybug' that she realized that something in her appearance and obvious strength reminded him of the superheroine.
She sighed, "Please don't tell me that you're Cat Noir?" She dreaded asking that question, but something did seem a little more than just the Adrien that she remembered from Lycee.
"I am." He mumbled as quietly as he could, and despite her own dislike of her identity being found out by a regular Wellness Checkup, she couldn't help but feel at least a little relieved.
"I am Cat Noir, and I'm your doctor this evening." He shrugged, and she bit back a giggle as it shouldn't be this funny; somehow the idea of Cat Noir wearing a doctor's uniform over his superhero one planted itself in her head and refused to go away.
"I'm Ladybug, and I know as well you know now that I'm perfectly healthy." She chimed in with a happy smile, hoping that no one entered the room then to hear their confessions to being superheroes.
"You are." Adrien's eyes twinkled.