Miley Cyrus is scared of getting dumped.

The 17-year-old singer worries her 20-year-old Australian boyfriend Liam Hemsworth could leave the US, and her, at any time.

In an interview with Ryan Seacrest on his KIIS-FM radio show, she said: "I don't want to be heartbroken. He could go back to Australia any second. But I'm happy. It's different from anyone else because he really is just an awesome friend too."

Although the pair have been dating for a year, after meeting on the set of movie 'The Last Song', Miley admits she has a crush on '17 Again' star Zac Efron.

She said:" He's gorgeous, he's hot, I don't go see his movies because I'm like, 'He's such a fantastic actor.' He's a great actor, but he's hot."

The 'Can't Be Tamed' singer also spoke about how she is determined to stay away from drugs, but is looking forward to being able to drink when she is old enough.

She said: "I'm not gonna be like, 'I'll never have a drink in my entire life,' because that's probably going to be a lie. There's a right way to do so - everything is good in small portions."