Manuel Mendez, Blue Ivy's stylist, shows WWD a typical day in his life.

Manuel Mendez is known to plan as many as 90 outfits at a time, all of which are for one very famous seven-year-old.

Much like her contemporary North West, Blue Ivy, the eldest daughter of Beyoncé and Jay Z, has made headlines in recent years for establishing herself as a young fashionista. Last year she wore a custom Valery Kovalska tuxedo pantsuit to the Grammy Awards and a Billie Blush dress in Jay Z’s “Family Feud” video. In July, she appeared in the video for “Spirit” from Disney’s “The Lion King” remake, in which she wore a custom purple tulle dress by Microwave and matching Alejandro Collection top.

Mendez is the fashion force behind these looks and others Blue has worn, as WWD confirmed last year, and has been quietly styling the young celebrity since before she was even born. He began his career with the Carters nearly a decade ago as Beyoncé’s personal assistant. In 2011, when the famed singer became pregnant with Blue, Mendez was tasked with keeping stock of and organizing the many gifts that poured in for the expecting mother. Eventually, that job turned into shopping for the newborn.

“There were things I couldn’t find and couldn’t get, and I’ve always been the personal assistant that [said], ‘I couldn’t find it, but I can make it,” Mendez said. “It started like that.”

WATCH: Blue Ivy’s Stylist Manuel Mendez Takes Us Inside His World

Born in Villa Juana, Santo Domingo, in the Dominican Republic, Mendez came to America when he was three years old. His grandmother was a sweater production knitter at a factory and would occasionally bring home extra work to earn overtime pay.

“I loved hearing the sound of the sewing machines and seeing my grandmother create sweaters,” he recalled. “I knew it would keep people warm from the cold.”

His mother, who owned a restaurant in New Jersey and sold jewelry on the side, taught him the value of earning an honest wage. He would help her drag coolers of cold water bottles around in the hot summer months so she could sell them in the park for $1.50 each.

In high school, Mendez began to cultivate his love for fashion. When forced to sign up for an extracurricular, he chose sewing.

“My first piece I had to make in the class was a baby shirt,” he said. “It was black with gold polka dots. I picked out the [simplest], easiest [option] — it was small, so I didn’t have to sew that much.”

For the past seven years, Mendez has styled Blue Ivy’s everyday looks, preparing as many as three outfits a day for her and, as of June 2017, her siblings, Rumi and Sir. Outfit preparations involve a combination of personal shopping — at stores such as Zara, Old Navy, Target and H&M — and custom pieces, some of which the public has seen and many of which it hasn’t.

Asked how often he creates custom pieces, Mendez said, “Every month, it’s different.” Factors include whether there’s a vacation, music video or other special occasion for which the children need outfits. Mendez has previously worked with The Blonds, Adrienne Landau and Raimana Cowan on custom pieces.

Styling for children comes with its own set of challenges that differ from styling for teenagers or adults. One is the obvious fact that kids outgrow their clothes at a faster pace than adults do.

“Kids today, they’ll be a size 10 shoe and then tomorrow, they’re like, ‘I don’t fit these sneakers anymore,’ and you have to start all over,” Mendez said. “You could be in the middle of customizing a piece for a specific project and it might take a designer 10 days or 30 days to make. You’ll have measurements now, but God forbid, next month is the event [and] they outgrow it. I’d rather something be too big than too small.”

The possibility of an unexpected growth spurts keep Mendez in a constant state of closet rotation and on the hunt for new pieces. He is big on recycling garments for siblings and other family members and, for custom pieces that warrant it, opts to put them into storage. In many cases, Mendez donates outgrown or unworn pieces.

“Coming from the Dominican Republic, so poor, I see so many kids and families with no shoes and clothing,” he said. “Knowing that donating it is going to help a family, it’s the best thing for me to do.”

Despite giving WWD a glimpse into his everyday life, Mendez is highly guarded when it comes to answering questions about his clients. He recently opened up his roster, though he declined to divulge exactly who he’s working with besides the Carters.

He also declined to answer questions about the average budget he’s generally given to work within.

Discretion is always top of mind when disclosing any personal information about my clients, so I don’t speak on them,” he said, adding, “I don’t have time for damage control.”

He is now working on launching his own brand — “Manu Man LLC has been registered,” he said. Having built his own Rolodex of designers capable of or interested in creating custom children’s pieces, Mendez knows how to navigate that world — and he has some advice.

“It’s hard at times to find over-the-top couture pieces for children,” he said. “You don’t find Alexander McQueen. You have Gaultier for kids, which is so cool, but they’re not making that anymore.

“Designers should [create more children’s pieces] if their business allows it as far as production,” he continued. “You have to have a whole new set of people catering to and focusing on that. I come across a lot of parents as I shop and I have conversations with them. They’re always like, ‘It’s so hard to find cool things for kids.’ Thank god for Zara, thank god for H&M. Even Old Navy is so trendy and Target, you find really cute pieces now. I look at a men’s fashion show and I look at those pieces for adults and I’m like, we need more of that. That’s why I started customizing a lot because I didn’t find those key pieces that I liked.”

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