Some prefer the pairing name as Alvinatty or Bralvin.
Alvin Seville and Brittany Miller are the love/hate relationship couple that often runs as a gag throughout the cartoon series. Brittany and Alvin are constantly picking on each other, yelling at each other, betting with each other, and trying to prove the other wrong, sometimes leading to great misunderstandings or adventures. Whether or not these confessions are puppy love, a crush, or real feelings is unknown, but under all the tension, they are shown to truly care for one another. They are shown as being married in the future in one episode of the cartoon series. Alvin and Brittany were rivals.
- In The Chipettes, Brittany falls backwards, and Alvin catches her, and when she walks into the closet accidentally (out of being nervous) and screams, Alvin, with a worried expression, lets her out.
- In Merry Christmas, Mr. Carroll, Alvin is naming off people he wants to tell about his wish list. He starts naming a few people he knows, but the 4th one he says is "BRITTANY" and he pauses and smiles, and continues on.
- In I Love The Chipmunks Valentine, Alvin tries several times to ask out Brittany. When Brittany turns down Alvin's invitations to go to the dance, Alvin is hurt and goes into a state of shock. This shows that Alvin really had his heart set on going with her and that he has feelings for her.
- In A Little Worm in the Big Apple, when Brittany was conned by "Uncle" Harry, Alvin helped her get back at him.
- In Mind Over Matterhorn, when Alvin sees that Brittany is depressed because The Chipettes are not as famous as The Chipmunks, he vows to make her the "Queen of Rock 'n Roll" as Alvin is the "King."
- In Cinderella? Cinderella!, when Cinderella (Brittany) walks in, Alvin says "the girl of my dreams."
- In Hooping It Up, Alvin has come to Brittany's rescue, during which time the song "My Boyfriend's Back" is being sung. When Alvin comes into the door, before the song starts he says to the boy with Brittany's hula-hoop, "Go ahead, make my day! Try to touch my woman!" this is obviously a threat that if he hurts Brittany, he'll do unimaginable things to him, showing he shows deep concern for Brittany.
- In Big Dreams, Brittany and Alvin are married. After the time machine breaks the first time and Brittany sees that they are married and rich, she tells Alvin "What could be better than what we just saw?", meaning she wants to marry him and spend the rest of her life with him.
- In The Brunch Club, Alvin grabs Brittany by the waist and they swing off on the flag rope.
- In The Legend of Sleeping Brittany, Brittany falls into a deep sleep after pricking her finger on a spinning wheel. Alvin's kiss revives her.
- In the intro dialogue of the song "Stand By Your Man," Alvin refers to Brittany as "lovepuddle."
- When the song "Get Munk'd" was playing Alvin takes Brittany's hand and dances with her.
- In Island Fever, when Brittany was feeling depressed, Alvin comforted her.
- Alvin says to James Ingram to sing a song he wrote for Brittany - "I Don't Want To Be Alone For Christmas (Unless I'm Alone With You)." In this song there are many times where Alvin calls her "babe" or "baby", and there is a part where Alvin wrote that he wants to kiss her beside the Christmas tree. He also says four or five times that he wants to hold her close. At the end of the song, Brittany says thank you and that it was beautiful and forgives him. They become passionate for each other because now Brittany knows that Alvin loves her with all his heart, and even enough that he gets James Ingram to sing a love song to her.
- In Alvin and the Chipmunks Meet the Wolfman, Alvin teased Brittany several times, hinting he likes her. Later on, they dance together.
- In Alvin and the Chipmunks: The Squeakquel, they first meet in school and Alvin falls in love with her. While rehearsing, Alvin says "I never thought I'd say this, but... pink is my new favorite color!", he's obviously talking about after seeing Brittany, he thought she was so pretty, he joked about it being his favorite color.
- In Alvin and the Chipmunks: The Squeakquel, The Chipmunks fall all over each other when rehearsing and smile happily while sighing, and all make comments about which Chipette they have a crush on.
- In Alvin and the Chipmunks: The Squeakquel, Alvin warns Brittany about what Ian did to him and his brothers. Alvin's advice shows he cares for Brittany and doesn't want her to get hurt by Ian.
- In Alvin and the Chipmunks: The Squeakquel, Alvin bumps into Brittany on the tray, causing him and Brittany to laugh nervously and get embarrassed.
- In Alvin and the Chipmunks: Chipwrecked, Alvin called Brittany "kind of the smart one" in response, she blushed.
- In I Love The Chipmunks Valentine, Brittany shows much affection for Alvin.
- In Sisters, Brittany (even if it was for her own selfish purpose), went to Alvin for help instead of Simon or Theodore.
- In Cinderella? Cinderella!, Brittany dreams that she dances with Alvin, showing us that Brittany shows affection for Alvin.
- In Experiment in Error, after an explosion in Simon's lab, she tricks Alvin into thinking he's turned her into a zombie so he'll feel guilty and take her to the ball after all.
- In Island Fever, when Alvin tries to comfort Brittany while she is depressed, she says she wouldn't want to be trapped with anyone else (except for Jeanette and Eleanor), meaning that she loves to be with him.
- Brittany sings "Stand By Your Man," with a little help from Tammy Wynette, in which she admits she loves Alvin despite his bad habits.
- In Dreamlighting, Brittany was preparing to see a romantic detective movie with Alvin. When Alvin calls Brittany to tell her he'll come after basketball practice, Brittany asks him what's more important, her or practice?
- In Big Dreams, Alvin and Brittany are married and have two twin boys.
- In Robomunk, Brittany kisses Alvin after she restores her boyfriend (Alvin) and brings him back to life.
- In many The Chipmunks Go to the Movies episodes, Brittany is either saved, dating, or a partner of Alvin's.
- In The Chipmunk Adventure, Brittany joins Alvin in a spear when they find out about the truth of the race.
- In Alvin and the Chipmunks Meet the Wolfman, Brittany dances with Alvin.
- In Alvin and the Chipmunks: The Squeakquel, after Brittany asked Ian if he could represent them, Eleanor says, "And hang out with the Chipmunks!!" Both she and Jeanette giggle excitedly, meaning they are already smitten with The Chipmunks from fame and inspiring them to sing.
- In Alvin and the Chipmunks: The Squeakquel, after Jeanette and Eleanor talk about Simon and Theodore, she says to them, "Yeah, I know. But, guys, remember what Ian said? We can't trust them." hinting she has a crush on Alvin, but has no choice except to follow Ian's rules.
- In Alvin and the Chipmunks: The Squeakquel, Ian lies about Alvin, and Brittany becomes really disappointed and appalled, showing she was interested in only meeting Alvin.
- In Alvin and the Chipmunks: The Squeakquel, near the end of the movie, Brittany and Alvin dance together and then smile at each other happily.
- In Alvin and the Chipmunks: Chipwrecked, Brittany tries to comfort Alvin after he doubts Dave will rescue them after he has driven him insane for a few years.
- In Alvin and the Chipmunks: Chipwrecked, when Brittany tries to comfort Alvin, she has a pink mark on her cheeks which signifies that she is blushing.
- In Alvin and the Chipmunks: Chipwrecked, Brittany paused and smiled at Alvin when he called her smart.
- In Alvin and the Chipmunks: Chipwrecked, Brittany held Alvin's paw multiple times.
- They are the leaders of their respective groups.
- They are very competitive.
- They are the most outspoken and can be extremely stubborn.
- They are pretty arrogant, selfish, and conceited, but will come through for their siblings in the end.
- They enjoy extracurricular activities: Alvin commonly likes football or basketball, Brittany is into cheerleading.
- Commonly they are the cause of many adventures/mishaps.
- They enjoy the spotlight/being the center of attention.
- They're not very wise to make decisions.