But in season three, she becomes more independent, and starts wearing colours such as dark emerald green, as well as more muted tones. "It's as opposite as we could go."

"We also changed her body shape to make her more mature, more sexy, less of a child," Glaser adds.

Meanwhile, the initial brief on Colin was that he should be "younger looking" than his two older brothers, "so we kept his colours more youthful," explains Dougie Hawkes, associate costume designer on Bridgerton.

But in the new season, Colin has just returned from his summer travels across Europe.

"He returns as a man, so the evolution from the boy's colours to the male dominant strength... was a drastic transformation," Hawkes explains.

As a result, Colin, who wore paler shades such as baby blue in the earlier episodes, is seen in much more striking hues this time around, such as navy blues and browns.

His clothes also allow for more movement and more of a swagger, according to Glaser.

Read More