Holly Brook Hafermann (born February 23, 1986), known professionally as Skylar Grey, is an American singer, songwriter, and record producer. In 2004, Grey signed a publishing deal with Universal Music Publishing Group and a recording contract with Linkin Park's Machine Shop Recordings under the name Holly Brook. Her debut studio album, Like Blood Like Honey (2006), served as her only release with the label.

In 2010, Grey co-wrote Eminem's hit single "Love the Way You Lie" with English producer Alex da Kid, who signed Grey to his record label Kidinakorner, an imprint of Interscope Records. Her second album, Don't Look Down (2013) peaked within the top ten of the Billboard 200, while her third, Natural Causes (2016) was met with critical acclaim despite failing to chart. Her 2021 single, "Last One Standing" (with Polo G, Mozzy and Eminem) marked her first entry—at number 78—on the Billboard Hot 100 as a lead artist. The following year, her self-titled fourth album (2022) was released independently to continued acclaim.

Grey is also known for providing guest vocals on several hit singles, such as Fort Minor's "Where'd You Go", Diddy's "Coming Home", Dr. Dre's "I Need a Doctor", Nicki Minaj's "Bed of Lies", and Macklemore's "Glorious". Additionally, she has written songs for a number of prominent performers including Kehlani, G-Eazy, Alicia Keys, Ciara, Christina Aguilera, Zedd, Nick Jonas, Céline Dion, and CeeLo Green.