Joe Jonas teases his brother Nick about his relationship with his 'The Voice Australia' co-star Delta Goodrem.

The DNCE singer appears alongside Delta, 33, on the show's judging panel and Joe has admitted he's taken the opportunity to tease his sibling about his ten-month relationship with Delta back in 2012, admitting it's been raised a ''few times''.

Appearing on 'The Kyle And Jackie O Show', Joe explained: ''There's a few times it has been brought up and luckily it's like a brother-and-sister relationship (between) me and her and we can really mess with each other and have a good time.''

Joe, 28, also joked that he'll be using the situation to his advantage on the singing show.

He said: ''It definitely helps. It definitely helps.''

This comes shortly after Joe's wife-to-be Sophie Turner revealed she was a troublemaker during her teenage years.

The 22-year-old actress - who announced her engagement to Joe in October last year - revealed that while she is more of a ''mediator'' these days, she used to be quite fiery.

Asked about her new movie 'Josie', and whether she identifies more with her character's troublemaking or mediating sides, she said: ''I think I used to be one that would stir up trouble. Now, I don't think I'm that so much; I'm more of a mediator.

''To be honest, I just stay out of everyone's business. I stay out of everything, I'm very impartial.''

The 'Game of Thrones' star insisted she has mellowed over the years, and she's now ''grown up''.

She explained: ''I'm definitely not a troublemaker anymore, but I'm sure I was when I was 17, 18. I just wanted to get into trouble. Now I'm an adult, you know? I'm grown up.''