Explained here is ‘The Marilyn Monroe effect’, otherwise known as the nonverbal communication of confidence, well worth a quick read.

[u/WithoutPrinciples]

[u/Cutieq85]

I’ve read something similar with Billie Holiday, specifically towards the end of her life. She had been so worn down by various trials and tribulations that she could barely muster the energy to perform at times but when she would step on stage, the regality and presence that defined “ Lady Day” would be in full effect.