The singer, who stars in musical comedy Bran Nue Dae with fellow Aussie stars such as Geoffrey Rush, Missy Higgins and Magda Szubanski, said that she initially was not sure if she could handle the role.
Mauboy told The Daily Telegraph: "I was like, 'Ahhh, you know I've done no acting in my life'. I was very nervous, especially with a couple of scenes I didn't know I was going to do, like the kissing scene.
"But it was like I was telling my own story. I felt really honoured to be able to play Rosie. There were lots of people who auditioned for it, especially locals, and I was lucky to get the part."
The 20-year-old star said of the Aboriginal film: "It really brought back the culture. That's how we grew up, we jammed in the back yard, and we were with family and having a laugh, being who we are."
Bran Nue Dae is due for release in Australia on January 14.