It Was My Best Birthday Ever, Charlie Brown is the 38th animated television special based on characters from the Charles M. Schulz comic strip Peanuts.

On his way back from a birthday party, he passes by a garden where he hears someone singing ("O Mio Babbino Caro").

As Linus is writing his guest list for his birthday party, Lucy asks who Mimi is.

Marcie, Shermy, Franklin, Clara (who Linus accidentally called Patty) and Frieda appear but do not have dialogue.

The song Mimi sings when Linus meets her is the "O mio babbino caro" ("Oh my dear Papa") soprano aria from the 1918 opera Gianni Schicchi by Giacomo Puccini.