The six-part series, written by Lucy Gannon (The Best of Men), will follow Frankie, a Bristol nurse who cares more for her patients than her own personal life.
Dean Lennox Kelly (Shameless) will play Frankie's boyfriend Ian, while Derek Riddell (Ugly Betty) will star as her team member and confidant Andy.
"This is an incredible leading part for a female," said Myles. "It's tremendous pressure but also tremendously exciting. I can't wait to step into Frankie's shoes and get on set. I'm desperate to start.
"Frankie is an infectious character, she's electric, quirky, wonderful at her job and adapts to every situation. She's a vibrant woman trying to live life in the fast lane and juggle a job. Lucy Gannon is an incredible writer and writes relationships so beautifully."
Julia Ford (News Tricks), Leila Mimmack (Inside Men) and Carla Henry (New Street Law) will also star in Frankie, which is currently filming in Bristol and will air on BBC One in early 2013.
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Watch Eve Myles discuss Torchwood with Digital Spy below: