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I know you were off fighting bad guys. I was upset. But, I guess that's a deal when you decide to date a superhero.

– Julie to Ben.[3]

Julie Yamamoto is Ben's ex-girlfriend and now friend. She broke up with Ben some time between The Ultimate Enemy: Part 2 and The More Things Change: Part 1.


Regular Appearances

In Alien Force and Ultimate Alien, Julie has black bobbed hair with straight blunt bangs, brown eyes, and wore a black T-shirt, mostly hidden under a pink hooded jacket, a white mini skirt and sported white tennis shoes.

In Omniverse, Julie now wears a white T-shirt. Her pink hoodie has light orange, yellow, and white stripes on it. Also, her hair is now longer and is kept in pigtails. She wears long socks with orange and yellow stripes that go up to her knees. She wears pink tennis shoes. Her Asian facial features are more pronounced.

Occasional Appearances

When playing tennis, she wears a white T-shirt and skirt, along with white wristbands.

During battles, she occasionally wears Ship as a form of armor.

In Save the Last Dance, Julie wore a white motorcycle helmet.

In The Perfect Girlfriend, she wore a white sweater and black pants.

In Inspector 13, she wore a light blue vest with a dark blue skirt, black leggings, blue socks and her usual shoes.


While normally kind, cheerful, spirited and good-natured, Julie can at times be very trying in that she is competitive and at times vindictive, stubborn to a fault, and very firm in the expectations she sets for herself. She is not the jealous type as she is too self-confident.[DM 2] She tries her best to be supportive of Ben but is often uncertain that he is truly supportive of her in the same way. Julie is also something of a tomboy, enjoying sports, Sumo Slammers, and movies and novels of the fantasy and science fiction genre the most.[DM 3]


Alien Force

Julie's first appearance

Julie first appears in Ben 10 Returns: Part 1, where she congratulates Ben after his team won a soccer game. She introduces herself and agrees to meet him at school the next day.

In Pier Pressure, Ben asked Julie out on a date. It was interrupted by Ship, who kidnapped Julie. During a rescue attempt, Julie found out about the Omnitrix, which she finds cool. In the end, it was revealed that Ship was trying to lead Ben to Baz-l, whose ship crashed and was about to explode. Ben and Julie helped fix Baz-El's ship and he left Ship with them, saying that he and Ben have a bond. On the walk home, Ship takes off after a passing truck, and Ben and Julie walk home, holding hands.

Julie and Ben

In Save the Last Dance, when Big Chill takes control of Ben's personality and starts eating every metal object in sight, Julie follows him on her motor scooter and alerts Gwen and Kevin. She also told them where Ben is headed. Gwen and Kevin manage to subdue Big Chill, only to discover that Big Chill was building a nest for eggs he had laid. The eggs hatch into baby Necrofriggians, and Kevin teases Ben about being a "mommy". As Julie takes Ben home on her motor scooter, she tells Ben that she thought he made a great "mom". Ben also stated that she gets straight A's.

Julie and Ship

In Pet Project it was revealed that Julie is keeping Ship as a pet; it put a strain on her relationship with Ben, as he feared Ship could do something that she couldn't handle. The Forever Knights kidnapped Ship, planning to use him to mass-produce spaceships to go to the Dragon's planet, brainwashing him. Julie managed to get through to Ship and bring him back to his senses. At the same time, she told Ben he wasn't the only one who saw Brainstealers From Outer Space; he skipped a date to watch a marathon of it. Julie would allow Ben and the others to use Ship's new spaceship form if they asked her.

In War of the Worlds: Part 1, Julie helped Ben fight against the Highbreed invasion and it turned out that she apparently had a curfew. She also seems to show a deal of concern and care for Ben. At the end of War of the Worlds: Part 2, Ben and Julie get close to kissing, but decided against it, as Gwen, Kevin, and Max were all watching. Ben then tells her that he will walk her to school the next day, and Julie gets home by riding Ship after giving Ben a loving smile.

In Don't Fear the Repo, the Vreedle Brothers, hired by Baz-El to return Ship to him. As Julie refused, the Vreedle Brothers started being more aggressive, and Ben and Kevin go in court to claim their right on Ship against Baz-El, while Gwen stayed on Earth to keep Julie and Ship safe. When the Vreedle Brothers came back, Ship revealed he can "merge" with Julie, giving her a powerful battle suit she can use to fight back against the Vreedle Brothers. Ben is eventually able to get the judge's favor, and Baz-El reluctantly accepts that Ship is now Julie's.

In Singlehanded, Julie finds Ben's detached hand and takes it to Gwen and Kevin. She later uses Diamondhead's hand to fight Sunder. During the fight, Gwen helped her keep Ben's hand away from Sunder but Julie wound up being used in a trade when Sunder caught her. After Sunder was knocked out, she, under Kevin's instructions, held a beam on Ben's arm while they used Sunder's axe to put Ben back in one piece and unknowingly sent Sunder to the Null Void as a result.

In the The Final Battle: Part 1, Julie is briefly seen playing with Ship.

Ultimate Alien

In Fame, sixteen year old Julie comforted Ben when his identity was revealed to the world. When he thought everybody would hate him, she kissed him on the cheek and told him that not everybody hated him.

Julie playing tennis in Duped

In Duped, Julie becomes very upset with Ben not spending time with her, as he chose to watch the movie version of "Sumo Slammers" as his real self while leaving an immature version of himself with her.

In Hero Time, Julie becomes jealous of Jennifer Nocturne after she kissed Ben when he saved her life. Later, she was kidnapped by Overlord. When he tried to kill her and Jennifer, Goop saved Julie. Goop then called her "his girl", and she smiles. She then assisted in taking down Overlord.

In Absolute Power: Part 2, Julie and Ship help Gwen escape Kevin. She later appeared in her battle suit for unknown reasons.

As shown in Eye of the Beholder, Julie and Ben were going through relationship troubles. Ben apologized to Julie for being such a jerk and he promised to try to be a better boyfriend, which makes them both happy.

In Revenge of the Swarm, when Ben and Julie arranged a date, she was kidnapped by the Nanochips at the behest of Elena, who was jealous of her. When Armodrillo freed Julie, Elena used the swarm in an attempt to suffocate Armodrillo. Julie was able to convince Elena to stop her Nanochip activity if she really loves Ben, as well as Julie herself loves him. Then she watches Elena kill herself to stop the Nanochips and Ben's life is saved. As Ben mourned Elena's supposed death, Julie gave him some comfort before they both drove home in Ben's car.

In Greetings from Techadon, Julie and Ben competed in a golf course and Ben won, thanks to Brainstorm, but Julie was shown not to be happy and accused Ben of cheating in the death hole. At the end of the episode, Ben went off to have a rematch as promised to Julie.

In The Flame Keepers' Circle, Julie joins a philanthropic organization called the Flame Keepers' Circle, as she accepts their theology of using Dagon's technology to advance Earth's humanitarian efforts and create a utopia. She tries to get Ben and Kevin to understand but fails, becoming quite angry at Ben for this as he laughed in the Cult Leader's face and he himself uses alien technology to protect Earth. She believed this to the point of pretending to be a hostage for Conduit Edwards to make Ben revert from Big Chill. She again tries to preach the benefits of the Flame Keepers' Circle to Ben, but realizes her mistake when Ben tells her that it is Vilgax. She maintains a belief that alien technology should not be kept from humans although is far less fanatical.

In The Perfect Girlfriend, Julie went off to Europe for a tennis tournament, during that time Elena impersonated Julie to try and win Ben's heart. Right after Elena revealed herself, Julie arrived at Ben's home, and was able to talk Elena down again when she tried to kill Ben, prompting her to leave swearing revenge.

In Night of the Living Nightmare, in Albedo's nightmare, Julie and Ship fought Ben and were defeated.

Julie and the rest of the team at the end of Ultimate Alien.

In The Ultimate Enemy: Part 1, Julie was playing a game of tennis when humanity was turned into Esoterica. She was able escape the mass transformation when Ship merged with her.

In The Ultimate Enemy: Part 2, Julie showed up after Ben stripped Vilgax of Dagon's powers and managed to talk him out of selfishly wiping out all evil. After Ben turned all of humanity back to normal, Julie kissed Ben on the lips for the first time in front of the others.


Julie appeared in Rules of Engagement with her new boyfriend and Ship. They are kidnapped along with Ester and Rook by Princess Looma. Julie fought Looma and with the help of Ball Weevil and Ship, she won. Ben and Julie then made an agreement to be friends after the break-up.

She later appears in The Most Dangerous Game Show as one of the females chosen to compete for Ben's hand in marriage. She is utterly uninterested in the contest, texting Hervé for the duration. This causes her to get knocked into the water during the "hole in the wall" round. After being sent to the Null Void with the other losers, she is later freed and returned to Earth.


In a possible future, Julie is now a sports celebrity. Whether or not she is still with Hervé is unknown.[DJW 1] She and Ben are still friendly when they see each other.[DJW 2]

Powers and Abilities

Julie playing tennis

Being an ordinary human, Julie doesn't possess any superpowers herself, although she's quite good at tennis, and showed some fighting ability when she took one of the Forever Knights electric maces and easily knocked out several Forever Knights.[4] Julie is the only one who can fully understand[5] and command Ship, making her a competent ally.

She can have Ship envelop her in "battle mode", that is, form an armored battle suit. In the suit, she demonstrates enhanced strength and great damage resistance, as well as the ability to fire powerful beams of green energy from blasters on the palms of her hands, as well as rocket launchers. She can also extend her arms,[6] and fly with rocket boots.


Without Ship's assistance, Julie is only an ordinary human without any superhuman capabilities.

In Don't Fear the Repo, if Ship gets paralysed; so will Julie.

In "battle mode", if Ship takes too much damage, he will come off of Julie.[6]


Alien Force

Season 1

Season 2

Season 3

Ultimate Alien

Season 1

Season 2

Season 3


Season 2

Season 8


Cartoon Network Action Packs

Chapter Books




Ever since Ben broke up with her, Hervé and Julie have been together. Unlike Ben, he is consistently there for her.


Yamamoto in Japanese means 'one who lives in the mountains’ or ‘at the foot of the mountain’, this is one of the ten most common surnames in Japan; it is found predominantly in the central and west-central parts of the country.


  • Julie never liked Mr. Smoothy, but never told Ben about it when they were together.[6]
  • Gwen considers that Julie is the "only one who has common sense among the four of [them]", as she always avoids trouble in every situation.[7]
  • Like Ben, Julie likes chili fries.[8]
  • Ben accidentally broke up with her over the phone while playing a video game of Sumo Slammers. Julie had believed that Ben's rude comments towards a game character were directed towards her.[6]
  • Julie still has feelings for Ben despite no longer being in a relationship with him.[MW 2]
  • Julie's Alien Force and Ultimate Alien design was created by Glenn Wong, with colors added by Chris Hooten.[GW 1]
  • In Alien Force/Ultimate Alien, Julie's battle mode had a similar appearance to the Power Suit of Samus Aran, the main character of the video game series Metroid.


Crew Statements

Derrick J. Wyatt

Dwayne McDuffie

Glenn Wong

Matt Wayne

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