You're walking with Monika, chatting a bit, as you continue walking, Monika noticed--

OMG IT'S HATSUNE MIKU!

She's a lot younger and she smiles at you. Once she sees Monika, she excitedly jumps up and down while making subtle 'beep-boop' sounds.

Hatsune Miku: "Hello! Are you Monika for Boki Boki?"

Monika: "..It's Doki Doki.."