She was played by Moriah Angeline.
When Rick started getting death threats, Mattie asked Nancy Drew to come out to New York and investigate.
Mattie is a white female with light brown hair. She is approx. thirty and seems to wear the same red dress suit on every occasion that isn't acting, and even then...
Mattie is a softie and wants to help Rick, but yet still feels hurt by him leaving her.
"Oh Nancy, this is horrible! Another attempt to get Rick! All of these threats, and now fella's almost murdered on stage! I'm too upset to deal with this! I gotta get out of here! I need some space! We'll talk later." - Mattie the Softie
Unsurprisingly enough, the girl keeps a picture of Rick smiling excitedly.