But luckily for the songstress, Themeli is ‘very supportive’ of her career, and co-star James, 28, was there to guide her through the experience.
‘Poor James,’ Jessica says, laughing. ‘All he heard from me every time we had to lock lips, I was like: 'I’m sorry, I’m sorry' – I couldn’t help it!
‘There were moments where I was like: 'I need 10 mints or I need to brush my teeth again!''
However, allowing the Darwin-born star to feel more comfortable during the filming process was her involvement as a co-producer.
‘It’s not like I was taking my clothes off or anything,’ she explains. ‘I couldn’t handle that, I couldn’t do it, I was really strict about that. I was very conscious of the respect and the dignity of me and of Billie. She doesn’t hop around.’
The 28-year-old tells New Idea that she struggled to break the news about her character’s romance to long-time boyfriend Themeli Magripilis.
‘I was so nervous,’ Jessica remembers. ‘We do this thing where he will help me out and I’m like: 'Bub, can you help me out with reading the other part,' and he will read it with me.
'There were moments where he was like: 'Oh hell, I hate this.' It was so hard for him to see that and feel that.
‘For him to pick up the scripts and read them, I felt more embarrassed than he did.’
Beloved by fans of her music and now her acting, Jessica is renowned for her squeaky-clean image and family values.
‘I am always asking myself questions,’ she reveals.
‘Why do I do it? What exactly do I want to do? How do I want to look?’
The star adds: ‘I need to feel comfortable.’
For the full story, and more entertainment news, see this weeks issue of New Idea - out now!