You adds Charlotte Ritchie as the female lead for the Paris-set Season 4

Deadline

The star of the British version of Ghosts will play a character named Kate who is "fearsomely smart, independent, suspicious, misses nothing. She is fiercely loyal to her friends, a brick wall to everyone else," according to Deadline. Her character "prefers 'arrangements' to love, which is why she dates fun but self-centered partier Malcolm. When Malcolm invites Joe (Penn Badgley), an American outsider of no apparent means, into their privileged world, Kate not only immediately dislikes him, she strongly suspects something about the man is not what he seems."