The period series - starring Joanna Vanderham and Sarah Lancashire - tells the story of a love affair against the background of England's first department store opening in the 1870s.
Darvill will make a guest appearance in the fifth episode as Bradley Burroughs, a barber who comes into conflict with the dashing Moray (Emun Elliot).
When Moray seeks to extend The Paradise by buying up Bradley's shop, the barber seeks to become his business partner, but his ambition quickly places him in grave danger.
30-year-old Darvill is best known for playing Rory Williams on Doctor Who and will make his final appearance on the sci-fi drama this Saturday night.
He also featured in the BBC's adaptation of Little Dorrit in 2008 and will next be seen in ITV thriller Broadchurch opposite former Doctor Who actor David Tennant.
The Paradise begins tomorrow night (Tuesday, September 25) at 9pm on BBC One.