Keira Knightley has joined the cast of Apple TV+'s new show 'The Essex Serpent'.

The streaming giant is working with See-Saw Films - the production company behind 'The King's Speech' and 'Top of the Lake' - on an adaptation of Sarah Perry's 2016 novel of the same name.

As reported by Deadline, Keira will take on the lead role of newly widowed Cora in the upcoming period drama.

Perry's book - which is set in 1893 - follows Cora as she relocates from Victorian London to the village of Aldwinter in Essex are being released from an abusive marriage.

There, she becomes intrigued by a local superstition involving a mythical creature - the titular Essex Serpent - which is said to have returned to the area.

The small screen adaptation has been written by 'Mrs Wilson' scribe Anna Symon, while 'Dark River' director Clio Barnard will be at the helm.

The drama follows 'Slow Horses' - which stars Gary Oldman - as one of a number of Apple TV+ commissions coming from the UK.

The platform has also worked on 'Suspicion' - featuring Uma Thurman - which is a remake of Israeli drama 'False Flag'.

Meanwhile Keira, 34, recently joked she will no longer strip off for nude scenes because her ''nipples droop'' after having to children.

The proud mum - who has Edie, five, and Delilah, 11 months, with husband James Righton - was happy to strip off for the cameras when she was younger but admitted she is no longer comfortable with filming nude scenes after having kids.

She quipped: ''The nipples droop! I'm really happy with my body. It's done an amazing thing. But I also don't want to stand there in front of a whole film crew.''

The star also admitted she has another reason for no longer doing nude scenes in her movies.

She explained: ''You can take the whole thing and put it in a completely different thing, and it's on some porn site.''