Australian actress Ariel Kaplan has been in a secret romance with her onscreen brother for nearly a year.

The Neighbours star is dating Harley Bonner, the actor who plays her character's twin brother, and they have been keeping their romance under wraps in recent months.

She tells Australia's Soap Extra magazine, "I love him more every day. It's all really good. I am very regimented and organised and Harley is pretty much the most laid-back person in the world. I made him a little bit more on time and he relaxed me. I am really happy when I am with him. He is a very good person and he makes me feel like a better person."