Felicity and Imogen Poots have been cast as the leads in
Trap for Cinderella, an adaptation of Sebastian Japrisot's novel by Iain Softley. The story revolves around a girl, Micky, "who wakes up with amnesia, terribly burned, after a house fire in which her childhood friend Do died. As she recovers, she begins to suspect that she may actually be Do, and involved in a plot to murder her friend."
It's unclear so far who is playing who.
This article also refers to Bill Nighy and Brooke Shields as being in the cast, but I think the writer made a mistake/or worded his article poorly, and is in fact referring to
Chalet Girl.
Lots of new projects for Miss Felicity!
Edit: Here's the
Variety article about Cinderella. They describe the plot as "two women, one wealthy and the other poor, who are trapped inside a beach house in a French resort when it is gutted by fire. Only one of them survives, burnt beyond recognition and in a state of total amnesia, unaware whether she is the heiress or penniless friend."