Kiss And Make Up, a song that is yet to be released, brings together one of the biggest pop stars in the world, Dua Lipa, and one of the hottest K-pop girl bands, Blackpink.

But the much-anticipated collaboration track was actually a song that was left on the back burner, Lipa, 23, reveals to The Straits Times just hours before taking to the Padang Stage at the Formula 1 2018 Singapore Airlines Singapore Grand Prix on Sunday.

"While I was writing for my next album, I was listening to some of the songs I hadn't put on the first album to see if there was anything worth keeping, putting out or giving to other artists," says the British singer, who added that she had written the song Kiss And Make Up with her friend Chelcee Grimes two years ago, before the release of her debut album.

Lipa and Grimes wrote the tracks Dreams and Bad Together on her debut, eponymous 2017 album.

"It was going to be on my first album and I wanted it to be a collaboration, but I couldn't find a proper home for it and I didn't know who I wanted to do it with," she says.

All the song needed was the right fit and it turned out to be four-member Blackpink, who are responsible for chart-topping hit Ddu-du Ddu-du.

"When I was last in Singapore (in May), I also went to Seoul, and Jennie and Lisa from Blackpink came to the show and I met them and we hung out and we got on really well," she says.

"I thought I should send (the song) to Blackpink and see if they'd be into joining it... they translated some of the song into Korean and that was that."

The track has now found a home on the reissue of her album, which will be released on Oct 19, alongside previously unreleased tracks Want To and Running.

But all eyes are on the new era of Lipa and her next album.

"It's still a pop album and I'm still working with the same producer I worked with on the first album, except we've taken a kind of more nostalgic turn," says Lipa, who remains tight-lipped about her upcoming work.

When asked if her current single Electricity, which takes inspiration from classic Chicago house music, is what she means by "nostalgia", she says: "I don't really know how to explain it yet, I haven't quite figured it out and I've not come to the finishing process."

As for when the album will be out, she says: "I'm still working on it... I would like to start putting out something maybe next year, but we'll see."