Sister is the sixth studio album by American pop duo Frost Children. It was released on September 12, 2025, via True Panther Sounds and Dirty Hit in vinyl, CD, cassette and digital formats. It includes four singles released in mid-2025, including "Control", "Falling", "What Is Forever For", and "Bound2U". Preceded by the duo's 2023 release, Hearth Room, the album consists of fourteen tracks ranging between two and four minutes each, excluding "2 Løve", whose runtime exceeds five minutes. It includes collaborators German singer-songwriter Kim Petras on "Radio" and English singer and producer Babymorocco on "Ralph Lauren". "Control" was released as the album's lead single on June 3, 2025, alongside a music video directed by Ben Turok. The duo released "Falling" as the second single on July 1, 2025, with Lotus Blossom directing its music video. It was noted by Stereogum as a "sleazy, bombastic summer anthem," and the music video as "full of neon, chains, anime." On July 31, 2025, the third single, "What Is Forever For", was released with a music video directed by Angel Prost of the duo. It was followed by "Bound2U", the fourth single, on August 27, 2025. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.