The actress said she is delighted to be reprising her role as Mandy Richardson after two years away from the Channel 4 soap.
She is quoted as saying: "I always said 'Never say never' so it was nice not to be killed off.
"I don't think I can look as it as going back because it's still a job in the industry and when you're an actor you just want to be working."
She added: "Hollyoaks is riding such a wave at the moment - it's a great time to be there."
Dunn, 26, has a small role in upcoming Batman movie The Dark Knight.