"No phone no cares, I was dumb and so young".

Charli XCX and Troye Sivan have teamed up for new single ‘1999’, and it’s a massive slice of nostalgia-tinged pop.

The collaboration sees the two reminiscing on the turn of the millennium – with references to Britney Spears and Slim Shady being littered throughout.

“Yeah, I remember back home Best friends, all night, no phone no cares, I was dumb and so young”, the pair sing on the track.

The pair previously teased the collaboration as they shared the single artwork – which appears to take strong influence from the Matrix.

Describing working with Sivan, Charli wrote on Twitter: “JUST WANNA TAKE A SEC 2 SAY HOW HAPPY I AM TO BE DOING A SONG WITH @troyESIVAN. TROYE IS HONESTLY 1 OF MY FAV ARTISTS & I THINK WHAT HE’S DOING FOR POP MUSIC IS INCREDIBLE & SPECIAL & EXCITING. I FUCKING STANNN! LUV U TROYE! 1999 DROPS MIDNIGHT TONIGHT! PS SORRY 4 YELLING.”

The new track follows the release of Sivan’s second album, ‘Bloom’, in August. Read NME’s five-star review.

Charli’s latest release, ‘Pop 2’, arrived last year. The soloist has since shared songs including ‘No Angel’, ‘5 in the Morning’, and ‘Girls Night Out’.

Read more: Troye Sivan hits back at Eminem’s homophobic slur: ‘Some words are not meant for anyone’
Meanwhile, a documentary about Charli was aired last month on BBC World Service.