Miley Cyrus’s new music has been influenced by her relationship with fiance Liam Hemsworth and politics, she said.

The US pop star opened up about rekindling her romance with the Hunger Games star and explained they had to “re-fall” in love with each other after having changed during a few years apart.

She also spoke about how she had recently stopped smoking cannabis and drinking alcohol.

Miley, 24, said her new single Malibu, from her as-yet untitled forthcoming album, is a love song about Liam, and that she felt the need to put it out because people were “going to talk” about them anyway.

She told Billboard: “They’re going to talk about me if I come out of a restaurant with Liam.

“So why not put the power back in my relationship and say, ‘This is how I feel’?”

Miley and Australian actor Liam, 27, were initially in a relationship from 2009 until 2013, during which time they were engaged. A few years later they reunited and are once again engaged.

The former Hannah Montana star said she “needed to change so much” following their initial split.

She added: “And changing with someone else not changing like that is too hard.

“Suddenly you’re like, ‘I don’t recognise you any more’.

“We had to re-fall for each other.”

Of her new, cleaner lifestyle, she said: “I used to (resist changing). But I haven’t smoked weed in three weeks, which is the longest I’ve ever (gone without it).

Liam Hemsworth and Miley Cyrus Liam Hemsworth and Miley Cyrus in 2012 (Tony Di Maio/PA)

“I’m not doing drugs, I’m not drinking, I’m completely clean right now.

“That was just something that I wanted to do.”

Politics is another point of reference with Hillary Clinton supporter Miley.

She said: “My record is political, but the sound bite doesn’t stop there.”

The Wrecking Ball singer said there was more to her album than politics, and that “getting my album smashed in the streets” was not what she wanted.

“I want to talk to people in a compassionate, understanding way, which people aren’t doing,” she said.

Miley Cyrus Miley Cyrus (Ian West/PA)

“I like the way I think right now. But don’t Trump supporters like the way they think?

“So I’ve also got to be open with the way I approach people with my opinions.

“That’s the only way to make real change.

“And it’s not because I want to sell records.

“I know now the ways that don’t work, because I went really hard during the ­election.

“But at the end of the day, we lost. We won, but because the system is f***ed up, we lost.

“I thought, ‘Okay, I learned my lesson on this one’.”

Of her post-election appearance as a coach on The Voice, she said: “By sitting there after the election in head-to-toe pink, while on the inside being a gender-neutral, ­sexually fluid person, hopefully that was saying ­something.

“I needed some sparkle in my life, to make me able to deal.

“Radiating love is ­something that is important to me – hopefully, that is being political.”