Person A is excited to show Person B their favorite movie/show of all time, and spends the time before it starts (the previews or the opening) gushing about how great their favorite character is and how B will love that character too. When the movie/show starts, though, something becomes clear: A’s favorite character is incredibly similar to B in looks and/or personality. Whether or not B points this out is up to you.
Bonus: B’s favorite character turns out to be the one most like A.
OT3 bonus: B’s favorite character is most like C, and C’s favorite character is most like A.
Meta-bonus: If the movie/show they’re watching is one that exists in real life, A’s favorite character is also played by the same actor/voice actor that B is.