Kate Middleton's influence in fashion is as strong as ever.

During Prince William and Middleton's four-day Scandinavian tour earlier this month, the Duchess of Cambridge styled her hair in a glamorous updo using a hairnet. When Middleton's fans learned that the secret to her hairstyle was a hairnet, they purchased the hair accessory in droves. Middleton's Kate Effect has apparently boosted the sales of hairnets big time in Superdrug. The hairnet that Middleton used can be purchased at $1.52 in retail stores.

Hairnet sales have reportedly increased by 40 percent following Middleton's high-profile royal tour. The hair accessory, which is often seen in professional kitchens today, has been an essential part of keeping a woman's hair in place for decades.

"Sometimes the classics are the best and the hairnet is a great example of a simple idea which can achieve the best results - without the need for fancy technology or expensive ingredients," Meg Potter, Superdrug head of beauty, told Daily Mail's Femail.

"To hear a humble hairnet is the secret to keeping The Duchess' updos in place and looking sleek is a far cry from all the usual high-end gadgets and beauty lovers have rushed out to pick up hairnets in a bid to recreate these fabulous looks," she added.

Meanwhile, Middleton's hairdresser, Amanda Cook Tucker, shared a snap of her travel essentials for the Duchess of Cambridge's royal tour in Sweden and Norway on Instagram. In the photo are combs, brushes, curler, blow dryer, different volumizing products and hairnets. However, shortly after Tucker posted it, she deleted her account.

"I'm not surprised Kate's hairdresser has such a substantial kit for the Royal Tour," celebrity hairdresser Jason Collier said about Tucker's post. "We've come to expect Kate to look impeccably groomed and glamorous, and she is so famous for that beautiful blow-dry that it always needs to look perfect."

Aside from Middleton's hairdresser, the Duke and Duchess of Cambridge's royal tour entourage for their Scandinavian tour included her private secretary Catherine Quinn, and stylist Natasha Archer. Jason Knauf, member of the press team and communications secretary, were also on board, along with Katrina McKeever and Charlotte Pool of the press team.