XO, Kitty' Season 2 showrunner Jessica O'Toole explained how the Noah Centineo cameo came together in an interview with Deadline.

Noah Centineo guests stars in XO, Kitty season 2, episode 2: 'Kiss and Make Up'. In the episode, Peter visits Kitty at KISS while taking part in an international lacrosse tournament in South Korea. He also hand delivers her a pack of letters that Simon wrote to her mother. Lara Jean found them and made Peter give them to Kitty.

Alex, the adorable Australian teacher who supported Kitty throughout season one, is barely in season two at all, and even Yuri feels less important to the story by the time this shorter run comes to an end. That's also the case with Praveena, who starts out strong before fading into the background as other stories jostle for centre stage.