Alexander Guy Cook (born 23 August 1990) is an English music producer and the head of the now-closed UK record label PC Music. Best known as executive producer for Charli XCX, he has also collaborated with PC Music artists such as Hannah Diamond, GFOTY, Finn Keane (as Thy Slaughter), Danny L Harle and Felicita, and has multiple aliases under which he releases music including Life Sim and DJ Warlord.

Since founding PC Music in August 2013, Cook's label represented over 20 artists releasing music within a similar style, in which tropes from mainstream 1990s and 2000s pop music are amplified. This style of exaggerated pop tropes grew to serve as the foundation of the hyperpop genre, which Cook is credited for developing and popularising.

Cook formed the one-off project QT with musician Sophie and performance artist Hayden Dunham, producing the 2014 single "Hey QT". He released his first solo singles in 2014, and was named #12 in the Dazed 100 for "redefining style and youth culture in 2015 and beyond". He served as executive producer on Charli XCX's mixtapes Number 1 Angel and Pop 2 (both 2017), and albums Charli (2019) and how i'm feeling now (2020).

Cook released his two debut albums, 7G and Apple, and received the Variety Hitmakers Innovator of The Year Award in 2020. In 2022, he co-produced the song "All Up in Your Mind" from Beyoncé's album Renaissance, which earned him a nomination for the Grammy Award for Album of the Year, and he released his third main album Britpop in 2024. He continued to produce for Charli XCX with Brat (2024) and its remix album, earning him a nomination for the Grammy Award for Best Remixed Recording for his "Von Dutch" remix.