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

Noah Centineo returns as Netflix's favorite boyfriend and this time, he's the one offering dating advice as he turns the tables on Kitty (Anna Cathcart)

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.