Nicola Coughlan's 'Bridgerton' costumes gave a hidden clue about her season three romance.

Nicola Coughlan will take centre stage in season three

Nicola Coughlan will take centre stage in season three

The 'Derry Girls' actress - whose character Penelope Featherington's romance with Colin Bridgerton (Luke Newton) will be the focus of the next series - ditched her usual yellow dresses for a more green-hued gown in episode four of the second season of the hit Netflix drama, and costume designer Sophie Canale has confirmed it was an Easter Egg.

Speaking to PEOPLE magazine, she suggested the colour change was meant as a subtle tease by combining Penelope's family's yellow palette and Colin's blue palette.

Referencing the upcoming plot, she said: "I've known for a very long time. I forgot actually that no one else knew until last night.

"That's useful as a tool to know where your characters are going as well."

She noted that combining the family colours was similar to the way she developed Phoebe Dynevor's alter ego Daphne's costumes in season one after her marriage to Simon (Rege-Jean Page), as her blue colour palette was blended with his reds.

Canale added: "When you see Daphne, we pushed her into lilacs in season 1 because of the marriage of the families and I think that's quite important to be seen."

She took over from Ellen Mirojnick as lead costume designer in season two, and she was determined to push "the characters in their own direction" through fashion.

She explained: "We're all so different as individuals. So it's really nice to take the foundation of their concepts and then push them a little bit further with elements of jewelry and hairpins.

"So there's a real distinction between the Bridgerton brothers [in season 2]. I really wanted to show the individual characters how they're developing through season 1 and how [in] season 2 they're now on another journey."

Meanwhile, Nicola recently opened up on the revelation her relationship with Colin will take centre stage.

Asked if she's prepared for filming raunchy scenes on set, she quipped: "I'm gonna have to be!"