A covert car ride and a lone USB stick - the secrecy surrounding Lorde's new single

The full story on how Lorde's new single was kept under wraps - until today.

It was a massive event - and it needed massive amounts of secrecy.

That's exactly what Lorde got when it came to the delivery today of Green Light, the first taste of the Kiwi pop star's new album, Melodrama.

The song, a high-energy dance-pop anthem with lyrics that reference a real-life break-up, had been teased out over the past week by Lorde.

The scattered promotional campaign started with an ad on TV on Monday night that showed Lorde sipping a milkshake in the back of a cab.

Over the following 24 hours, Lorde sent tweets saying things like, "U hungry," while directing fans to a random website called, imwaitingforit.com.

The milkshake, the cab, the "hungry" tweet made it sound like she was launching a new food delivery service to rival Uber Eats, rather than a new song.

Then, on Wednesday, she sent fans on a night time mission across Auckland to discover several art installations lit up in green while playing new snippets of music.

When Katy Perry delivered her recent single Chained to the Rhythm last month, she set up a disco ball in Britomart that fans could plug their headphones into.

In terms of record label marketing, Lorde's effort was next level.

Behind the scenes, even more secrecy was being enforced by her record label, Universal Music, to avoid potential leaks.

Dean Buchanan, NZME's group director of entertainment, first heard Green Light on Thursday last week when he was picked up in a white car by Lorde's record label.

Buchanan says he was approached on Monday by Universal with an offer of a car ride. No mention of Lorde was made, and he was asked to leave his phone in the office.

"All we were told was, 'There's a song we'd like to play you, please come'. They said, 'We'd love to drive you around the block in a lovely car with a great sound system... You're not allowed to discuss it with anyone'," he says.

Once in the car, Buchanan says he was asked to listen to the song twice - but he says he knew from just one listen that it was a potential hit.

"You can hear the braveness in this track ... the genius of it is it taps into multiple genres, but it's a pop song. It's an interesting song. When you hear it four, five, six times, you start to hear new stuff," he says.

"If you've been around for a few years, you know a hit when you hear it."

Fast forward to today. To avoid Green Light leaks, the song was delivered to NZME radio stations ZM and The Hits via a USB stick just minutes before the embargo lifted at 8am.

Listen: ZM's Fletch, Vaughan and Megan speak to Lorde

Buchanan says most songs are delivered digitally and it's "very rare" for new music to be handed to NZME on a USB stick.

But he believes it tied into the marketing plan around Green Light, which he applauds.

"It's rare, but I think the genius of Ella is that this is an event. There are very few artists you can do that for. Now we've heard the song, when you look at the world of music right now, there's not many better than her."

The build-up began more than a year ago, when Lorde sent the following tweet on January 1, 2016.

Along the way, there was a split with her Pure Heroine writing partner Joel Little, a teaming up with pop writer Jack Antonoff, a mini meltdown on Instagram, and a birthday update that promised fans new music wouldn't be too far away.

Today's release of Green Light was backed by a revealing interview with ZM, as well as a high profile slot of Zane Lowe's Beats 1 show on Apple Music.

All that for a single song. So the question remains, what happens when it comes time to deliver Lorde's second album?

Buchanan suspects it could be a while before fans get a full album.

He believes the campaign could be stretched out for months - past her headlining slots at Coachella and Governor's Ball and even held until Christmas.

"If I was a betting man, I'd say, 'Well, it's March, there will be a fair few more [song] drops, the Christmas market is huge'. She could use the festivals to play some of her new material, but not release the album and build demand.

"Maybe we don't see the album for a fair while yet. It's another part of the intrigue, which I love about what Lorde does."