Pop 2 is the fourth mixtape by English singer and songwriter Charli XCX, released on 15 December 2017 by Asylum Records. Executive produced by A.G. Cook of PC Music, sessions for the mixtape began just several months before its release and featured a wide variety of guest contributions. The project received praise from music critics, and was backed by the single "Out of My Head" featuring Alma and Tove Lo. The recording was to feature a contribution from rapper Lil Peep, which was shelved following his death in November. Collaborations which appear on the record include singer Carly Rae Jepsen, Brazilian artist Pabllo Vittar, Estonian rapper Tommy Cash, German pop singer Kim Petras and Korean-American hip hop artist Jay Park among others. Charli stated that "this mixtape isn't necessarily about me – it's really about giving everybody their moment to own the song." The first single from Pop 2, "Out of My Head" featuring Tove Lo and Alma was released on 8 December 2017 along the pre-order of the mixtape on digital platforms. The song "Unlock It" featuring Kim Petras and Jay Park was premiered on 11 December 2017 on radio program Beats 1, being named its release day's World Record. Another track called "I Got It" featuring Brooke Candy, Cupcakke and Pabllo Vittar was released on 13 December 2017 as the final promotional single before the mixtape's official release. At review aggregate site Metacritic, Pop 2 has an average score of 84 out of 100, based on 8 reviews, indicating