"Would you like me to source you a paper towel?"

Less than two minutes into an interview with Reneé Rapp – pop star, film star, Broadway actress, media sensation – and I have spilled an entire bottle of water onto the table.

Luckily, as a father of two, I carry a permanent supply of tissues (and plasters and sun cream and antiseptic) everywhere I go. Within seconds, the mess is mopped up.

"You literally have tissues with you? I'm so impressed," Rapp squeals... Before admitting her parents are basically the same.

"My dad brings hair bands everywhere because I'm always without a hair tie," says the 25-year-old. "So I know I'm going to be an insufferable parent.

"I'll be saying, 'please let me brush your teeth', and the kid's going to be, like, 17."

We meet in London's King's Cross, near Rapp's record label offices. She's a little frazzled after two days of live shows; and somewhat sleep deprived, thanks to a group of kids who have been running races in the corridor outside her hotel room.

Yet she's friendly and engaging, full of zingy quotes that confirm her reputation as pop's most unfiltered star.

That's a label she acquired while promoting last year's Mean Girls film. Rapp played central villainess Regina George, reprising a role she originated on Broadway, and spent the press tour gleefully going off script.

She tore into the owner of a bus company whose boss had been an "asshole" to her mum, declaring, "I can't stand you and I hope your business burns"; and praised co-star Megan Thee Stallion for having "the best ass I've ever seen in my life".

Elsewhere, she confessed to being "very publicly ageist" and said her only male crush was Justin Bieber, because he "looks like a lesbian".

YouTube is full of compilations with titles such as: "Reneé Rapp making her PR team question their life choices for 5 minutes straight".

The singer knows what media training looks like, she just doesn't vibe with it.

"I got on a phone call years ago where they were telling us how to answer certain kinds of question, and what not to say," she recalls, "and I just remember being like, 'This feels so boring to me'.

"I think it's a skill to be able to give a thought-out, fluffy answer. It's just not something that I want."

"Good interviews, to me, are like a conversation........

© BBC