What guitarist worked with both Earl Slick and Siouxsie and the Banshees?
Earl Slick: Earl Slick (born Frank Madeloni in Brooklyn, New York, October 1, 1952) is a guitarist best known for his collaborations with David Bowie, John Lennon, Yoko Ono, and Robert Smith. Robert Smith (musician):  He has also played guitar in the band Siouxsie and the Banshees.
Robert Smith