Miley Cyrus hasn't smoked marijuana for three weeks, the longest she's "ever gone without it".

The 24-year-old singer has never hidden her love of the recreational drug, wearing weed print tops and onesies and even making fiance Liam Hemsworth's birthday party in January (17) marijuana-themed. But in a new interview with Billboard magazine, Miley admitted she decided to quit the substance in a bid to get a clearer head to focus on her new music.

"I used to (resist changing)," Miley said. "But I haven’t smoked weed in three weeks, which is the longest I’ve ever (gone without it). I’m not doing drugs, I’m not drinking, I’m completely clean right now! That was just something that I wanted to do.

"I like to surround myself with people that make me want to get better, more evolved, open. And I was noticing, it’s not the people that are stoned. I want to be super clear and sharp, because I know exactly where I want to be.”

When it comes to her decision to stop smoking pot, Miley insists it was her call entirely. As if she had been told by other people to quit, she wouldn't have done it.

Asked if it had been hard to stop smoking marijuana, Miley replied: "It’s easy, dude. When I want something, it’s f**king easy for me. But if anyone told me not to smoke, I would have not done it. It’s because it was on my time. I know exactly where I am right now. I know what I want this record to be."

Miley is certainly no stranger to hitting headlines, and caused a worldwide storm when she twerked against Robin Thicke during their performance of Blurred Lines at the 2013 MTV Video Music Awards.

But the singer insists going out of her way to attract attention has never been her thing.

"(The record isn't about) wanting something from my fans or the audience, like some slimy thing - 'How do I get attention?' I never thought about that," she said. "Dude, I was shocked that people gave a f**k about the ­twerking, the teddy bear. It’s a totally ­different time, and I don’t think that would freak people out anymore."