Sadier has contributed vocals to various groups and projects, at times along with the late Stereolab member Mary Hansen. She and Hansen had contributed vocals to various recordings of The High Llamas and to the Tim Gane/Sean O'Hagan side project Turn On, and has contributed backing vocals to the track "Go Round" on The Hair and Skin Trading Company's 1993 album "Over Valence". Sadier added French backing vocals on the 1994 song "To the End," from Blur's "Parklife" album. In 1995, she recorded the Serge Gainsbourg/Brigitte Bardot song "Bonnie and Clyde" with Luna. Throughout the years, Sadier has occasionally collaborated with German electronica group Mouse on Mars. In 1997, Sadier sang on "Schnick Schnack Meltmade" on Mouse on Mars' "Autoditacker" LP, and she and Mary Hansen contributed vocals to the "Cache Cœur Naif" EP. In turn, Mouse on Mars produced tracks on Stereolab's "Dots and Loops" LP.