Guitar Hero is an episode of the ALVINNN!!! and The Chipmunks series.
Alvin begrudgingly agrees to teach Miss Smith guitar, but she won't reveal why she so desperately needs to learn.
Miss Smith dismisses the class with their next assignment before questioning Alvin about the one due now. Having failed to do the assignment, he is sent to detention. Miss Smith confides in Simon the she needs to learn guitar by the end of the week though Simon confesses he has no time, recommending Alvin instead. They both refuse until Simon leaves. Alvin tries to get a reason for him teaching her, but she refuses and receives a homework assignment instead. Convinced Miss Smith is hiding something, Alvin enlists Eleanor and Theodore to determine exactly why she wants to learn so suddenly. During Alvin's first lesson Miss Smith pretends to have done Alvin's assignment as he had done so Alvin resorts to trying to teach four basic cords. Meanwhile, the detective duo visit Miss Smith's home looking for evidence when a phone call from Miss Smith's sister, who brags about her achievements, startles them. Back in the classroom Alvin is frustrated by Miss Smith's lack of progress and the two feud before Alvin goes back to detention. Miss Smith tries her luck with other guitar instructors, however, each have their own problems. Eleanor and Theodore continue gathering clues around town and online before reaching the conclusion that Miss Smith's sister Clarissa is "perfect" and Miss Smith wants to do something to make her mother proud for her 90th birthday party. Learning the reason, Alvin decides to attempt to teach again, this time taking a new hands-on approach. During the party Miss Smith is nervous about making a fool of herself and Alvin reminds her of her gift to her mother. Miss Smith sings as she plays the guitar and her mother is brought to tears.
- "One in a Million" 
- The episode's title could be a reference to RedOctane's Guitar Hero video game.
- This episode reveals that Miss Smith has an older sister named Clarissa.
- Julie, last seen in the season one episode Mancave before suddenly disappearing, makes her first cameo appearance in season three. She can be seen sitting in the audience during Miss Smith's performance.