Willis has collaborated with Leftfield singing and writing lead vocals for "Swords" on the "Rhythm and Stealth" LP in 1999 on Hard Hands/Higher Ground/Sony BMG Records, which was also featured on the soundtrack for the film "Go" released 1999. The LP "Rhythm and Stealth" received a Platinum Sales Award in the United Kingdom. An instrumental remix was included in a single release by Two Lone Swordsmen, an electronic duo consisting of Andrew Weatherall and Keith Tenniswood. Willis has sung lead vocals to the track "Call of the Wild" on the Jimi Tenor album "Out Of Nowhere" in 2000 on Warp Records. Willis collaborated with Nuspirit Helsinki, with writing and vocal on the track "Honest" from the self-titled album "Nuspirit Helsinki" released 2002 on Guidance Recordings. Willis also wrote and sang vocals on the track "Are You Ready To Party?" with Mr Comicstore in 2006 on Mamushi Records. Willis collaborated with Flexatones Originals on tracks, "Cause I Want" & "Fresh" released on Fat Belt Records in 2007. Willis has contributed lead vocals to the Shawn Lee track "Jigsaw" featured on the album "Soul in the Hole" released in 2009 on Ubiquity Records. She has also sung vocals on the track "A Little Bit Of Soap" on the new album from Pizzicato Five's Yasuharu Konishi solo project titled Pizzicato One. The album titled "One And Ten Very Sad Songs" was released on May 25, 2011 on Universal Music in Japan. Willis collaborated with Jimi Tenor & Abdissa Assefa on track "Leatheries" from their LP "Itetune" released in 2011 on Temmi Kongi Records, contributing spoken words and poetry. Willis wrote lyrics and sang on the track "Bad For Me" by Bosq featuring Nicole Willis released by Ubiquity Records in 2014.