"1999" is a song by English singer and songwriter Charli XCX and Australian singer Troye Sivan, released as the lead single from the former's third studio album Charli on 5 October 2018. The single cover was inspired by the 1999 film The Matrix. It follows several singles released earlier in 2018 by Charli XCX and Sivan's 2018 album Bloom. The track reached number 13 on the UK Singles Chart dated 22 November 2018, becoming Charli XCX's tenth top 40 single and first top 15 single since 2015, as well as Sivan's fourth top 40 single and his first top 20 single. A sequel to the track, "2099", was released as a promotional single in September 2019. "1999" is playable in Just Dance Unlimited on Just Dance 2020. Background and composition Background The song contains nostalgic lyrical references to the titular year along with a snare-heavy beat, "fuzzy sawtooth bass and sparking Eurodance keys". Sasha Geffen of Pitchfork stated that the track is "more concerned with the act of remembering than with the specifics of the year it calls up itself" and "fits alongside the rest of Charli XCX's sleek, forward-looking pop songs". The song also references Britney Spears' 1998 debut single, "...Baby One More Time". Musical composition The song is written in the key of B minor, with an allegro tempo of 124 BPM in common time. Sivan's and Charli XCX's voices span between the notes B3 and F#5. Artwork The cover art references the 1999 film The Matrix, with Sivan dressed as Neo, wearing dark sunglasses, a black overcoat, and dyed black hair against a bright green background. Charli XCX, who is dressed as Trinity, flanks him. Billboard also noted its similarity to Aaliyah in the music video for her 2000 song "Try Again". Promotion Charli XCX and Sivan tweeted lyrics from "1999" addressed to each other on Twitter before both shared the cover art and title of the song. Music video The music video was released on 11 October 2018, and features Sivan and Charli XCX in various homages to 1990s pop culture, including the iMac G3 and Steve Jobs, Britney Spears and Justin Timberlake,' Spice Girls,' New Radicals, Eminem, the Nokia 3310, Rose McGowan and Marilyn Manson, the films Titanic, The Matrix, American Beauty, and The Blair Witch Project, the Dancing baby, the video game The Sims, and the music videos for the songs "Say You'll Be