Simon Seville, temporarily known as Simone while under the influence of a spider bite, is one of the three main characters in the live-action Alvin and the Chipmunks franchise. He is Alvin's and Theodore's brother.
He is voiced by Matthew Gray Gubler.
Simon is a chipmunk with large glasses and has blue eyes and wears a blue hoodie. When he was Simone, his sleeves were ripped and he had a bandana tied to his head.
Simon is the nerdy brains of the chipmunk trio. He is a very intelligent and calculative genius who acts as the voice of reason behind his brother Alvin and always figures out the complications he and his brothers face. As Simone, he is a brave and charismatic womanizer who speaks in a French accent. He was also an athletic jungle guy and shares a romance with Jeanette, his female counterpart of The Chipettes.
Alvin Simon and Theodore are three chipmunk brothers whose tree was cut down and they ended up stowing away in the bag of Dave Seville. When Dave discovers them, he is freaked out that they can talk and nearly kicks them out until he hears them sing and decides that they can work together to be in JETT Records. After teaching them a couple of Christmas songs, Dave presents them to his boss Ian Hawke. However, The Chipmunks are too nervous to sing due to stage fright. Feeling guilty, The Chipmunks go to Ian's house and sing the song. Ian signs them to JETT Records and makes them an internet sensation wearing sweater vets with their initials on it. Ian lies to The Chipmunks that Dave is holding them and that they should live with him instead. After finding a letter Dave hastily wrote when he angered at them failing their audition earlier (though Dave had a change of heart when they became famous and forgot to throw away the letter), The Chipmunks that Dave doesn't want them anymore and call Ian to tell him that they are staying with him. However, life with Ian isn't as good as they thought it was. Ian starts abusing The Chipmunks giving them a hyperactive energy to keep them going and switching Simon's glasses with tiny square ones that resemble his. Dave finds out Ian's treachery and rushes to The Chipmunks' concert to get them back. Seeing Dave, The Chipmunks realize that Ian lied to them and try to return to Dave. However, Ian catches them puts them in a cage and takes off in a limo with them. Fortunately, The Chipmunks are able to escape and leave bobble-head dolls of themselves in the cage instead. They reunite with Dave and quit JETT Records leaving Ian unemployed.
After Dave is accidentally injured during one of The Chipmunks' concerts, The Chipmunks are enrolled in high school and put in the care of Dave's nephew Toby Seville. They enter a contest to see who will sing in the school concert and compete against The Chipettes, with whom they fall in love with respectively. However, The Chipmunks are horrified when they find out that The Chipettes' manager is Ian. Simon also becomes jealous when Alvin starts hanging out with the football jocks and neglects his brothers, even pulling a prank on Simon by appointing him a fake position in the school called "litter monitor". To make matters worse, Alvin misses the competition to attend a football game. Unwilling to perform without Alvin, Simon and Theodore are forced to forfeit declaring victory to The Chipettes. On the night of the concert, The Chipettes find out Ian's true nature after he puts them in a cage to take them to a different concert rather than the one of the school in a limo. After Alvin rescues the Chipettes, both band perform at the school together. Dave recovers from the hospital and The Chipmunks let The Chipettes move in with them.
Dave takes The Chipmunks and The Chipettes on a boat cruise to take to the International Music Awards. Simon convinces Dave that they are responsible to spend a night alone in their suite while Dave goes out to a meeting. Dave agrees and lets them choose a movie to watch, but Alvin forces Theodore to watch a horror movie and sneaks out with The Chipettes to a casino while Simon chases after them. Eventually, they are all caught by Dave. The next morning, The Chipmunks and The Chipettes accidentally get blown away whilst playing with a kite and end up stranded on a desert island. There, they meet a lone survivor named Zoe who lets them stay in her hideout. Simon gets bitten by a spider and transform into a sleazy French jungle guy named Simone, who begins a romance with Jeanette. He also has no recollection of his friends and wonders who Dave is. Simone starts seduces Jeanette and charming her with his good looks and cheesy pickup lines. He also helps cross a bridge she was too afraid to cross alone. They go on a date and Simone discovers a cave behind a waterfall that contains treasure. He takes from the cave a golden bracelet and gives it to Jeanette. While they are preparing a boat to escape, Dave reaches the island with the help of the reformed Ian and reunites with his children. However, Zoe finds out about the cave and wants the treasure for herself only to find out that the entrance is only chipmunk-sized. She kidnaps Jeanette to force her to get the treasure for her and knocks out Simone with a golf ball, curing him of the spider bite and transforming him back into Simon. Simon wakes up when the gang finds him and has no recollection of his actions when he was Simone. The gang rescues Jeanette and Jeanette gives Zoe the bracelet Simon gave her.
Dave starts dating a woman named Samantha, who has an annoying son named Miles whom both The Chipmunks and The Chipettes hate. When Dave and Samantha go on a romantic getaway in Florida, The Chipmunks and The Chipettes suspect that Dave is going to propose and with Miles' help travel to Florida to stop the proposal. They then find out that the "proposal" was actually Dave's business promotion and make emends by singing with The Chipettes.