The Stacey Slater star has appeared in BBC Three's Being Human and Sky Living's Bedlam since leaving the BBC serial in 2010.
Recalling her decision to quit, Turner told PA: "It was a hard decision because I loved playing Stacey and I loved my time there.
"But it just got to a point where I'd been there for seven years and I was curious [about what else was out there] - and once I'm curious, I'm gone."
Meanwhile, the 24-year-old is appearing in new BBC improvised drama True Love alongside David Tennant, Billie Piper and Jane Horrocks.
She said of the experience: "That was another really great experience, to not have a script, and just to read a tiny bit of stage direction for a scene that could be a good six minutes long."
Before that, Turner will be seen on the second series of Bedlam, which launches on Wednesday, June 6 from 10pm on Sky Living.