Millie Gibson's parents called her "crazy" after she quit her role as Kelly Neelan on 'Coronation Street'.

Millie Gibson has joined the long-running sci-fi series

Millie Gibson has joined the long-running sci-fi series

The 18-year-old actress - who recently joined 'Doctor Who' as Ruby Sunday - shocked her parents when she revealed that she was quitting the ITV soap.

Speaking on the 'Conversation Street' podcast, Millie shared: "They thought I was crazy! They were like, ‘Why on earth?’

"It’s such a secure position. I was like, ‘Of course, but that’s what the thing is I don’t need to be secure at the minute.’ I need to spread my wings and see what can happen. And nothing could but I would have regretted it if I hadn’t tried, so I need to try."

Millie felt the time was right to leave the cobbles, as she'd already accomplished everything she could with the character.

Despite this, the actress admits that it was still a "hard decision".

She said: "Obviously 'Corrie' is the most incredible job you could ever think of getting, especially at my age. But you get to a point that you feel … I got the most out of it, the most out of the character, I’d explored so much with Kelly.

"I just thought whilst I’m still young I’d go and see what the rest of the world had to offer. It was a hard decision, for sure."

Meanwhile, Russell T Davies - the 'Doctor Who' showrunner - recently revealed that he watched Millie during her time on 'Coronation Street' and he's confident that she'll be a huge success on 'Doctor Who'.

He said: "It’s the great honour of my job to find the next generation of talent, and Millie shines like a star already. She’s brilliant, dynamic, clever and a wonderful actor.

"As a 'Coronation Street' fan, I’ve seen Millie survive chases, guns and sieges, but that’s nothing compared to what lies ahead for Ruby Sunday."