Julianne Hough has gushed that Mary J. Blige calls her "sister".

The two women star alongside each other in the new movie Rock of Ages and struck up a close friendship on set.

The 23-year-old dancer-turned-actress was nervous about singing alongside the R&B star, but knows Mary didn't judge her.

"There was a lot of downtime where we just bonded. We are really close. She calls and leaves me messages, out of the blue, all the time that are like, I just want you to know that I love you so much, Julianne, and you are so amazing.' She just boosts my confidence, every day. She said, I am here for you, whether I am your friend, your sister, your aunt, your mom. Whatever you want me to be, I will be'," Julianne told movie website Collider.

Julianne also revealed how she started out in Hollywood.

Now a successful budding star, the blonde beauty was determined to make it in the entertainment industry but it wasn't always easy.

"I had $2,000 in my pocket when I came to L.A. and I told my Dad I had $5,000, so I could move out here" she explained. "I remember that I lived with a bunch of models. They would do a job and get like $10,000 and I would be like, This sucks!' And then, they wouldn't work for a month. They would just be in their pyjamas when I left, and then, when I came home, they would still be in their pyjamas, while I was out working and auditioning. I thought they were so lucky. We are still really good friends now, but it was hard. I was working my butt off."