While she's best known for her Chelsea blow-dry and chestnut brown locks, the Duchess of Cambridge recently revealed a new, darker shade of brown after a six-hour visit to Rossano Ferretti's salon, the Daily Mail reports.

The new style may have even cost Kate Middleton a whopping $800, as she not only had her color changed, but reportedly received a "color and gloss procedure" that will help hide to conceal her gray roots, and debuted the new dark chocolate color at a SportsBall gala in London last Thursday, wearing her blowout mostly sleek and straight.

To ensure that there were no interruptions during her lengthy hair appointment, staff at the central London salon told customers that there was a "VIP in residence" and even shut off elevator access. 

"She looked amazing. She was dressed in a tartan cape and was made up. Her hair looked fabulous, really big and glossy, and it was flowing around her shoulders," a witness who watched Middleton leave the salon reported to the Daily Mail. 

While the pampering session may have cost her a pretty penny, it was the first opportunity for the Duchess to really treat herself since giving birth to her son Prince George, as the baby has taken up a good deal of her and husband Prince William's time. After seeing photos of herself with gray hair peaking through her roots, however, the Duchess was allegedly "horrified" and sought out Ferretti for a make-over.

Click here to see before and after photos of Kate Middleton's hair style.