Sofia Richie has a "special relationship" with Justin Bieber.

Sofia Richie in Billboard

Sofia Richie in Billboard

The 18-year-old model - whose parents are singer Lionel Richie and his ex-wife Diane Alexander - is believed to have been dating the 'What Do You Mean?' singer for the last few months and she enjoys hanging out with the 22-year-old pop star because he is "easy to talk to".

She told the new style issue of Billboard magazine: "We have a special relationship. Justin is very easy to talk to, and that's hard to find with people in Los Angeles."

Despite the attention her relationship receives, Sofia insists she doesn't care and has learned how to cope with the trickier sides of fame from watching how her older sister, Nicole Richie, coped in the spotlight.

She said: "I remember the paparazzi and the s**t people would say to Nicole, and she wouldn't respond.

"I'm going to be real with you: It. Doesn't. Bother. Me. As long as I'm happy."

Having Lionel as a father means Sofia has been around famous people all her life, but she still gets starstruck by some of his pals.

She recalled: "One night he intercoms me, like, 'Come have dinner in the studio'.

"So I go down and it's my dad and Pharrell Williams. I'm like, 'I can't just sit here and casually have a dinner with you two! I'm so sorry, I've got to go back upstairs.' "

But now she's legally an adult, Sofia is ready to move out of the family home.

She insisted: "It's time to go."

However, the 'Dancing on the Ceiling' hitmaker will miss having her around because she's a big influence on his wardrobe.

She said: "My dad can leave the house looking a little crazy. I have to tell him to change."

Read the interview with Sofia at http://www.billboard.com/articles/news/7502741/sophia-richie-style-issue-billboard-cover.