Musichetta is Joly and Bossuet's shared mistress.
In the books[]
Joly described her as a superb girl, very literary, with tiny feet, little hands, she dresses well, and is white and dimpled, with the eyes of a fortune-teller. Joly stated to Bahorel that he is wild over her.
Bossuet and Joly 'share' a relationship with her.