In December 1974, Genesis drummer Phil Collins was invited to rehearsals with a developing five-piece instrumental jazz fusion group at Island Studios in London, which included Percy Jones on bass. They had secured a recording deal with Island Records and prepared tracks for a studio album which originally included vocals. However, the vocals were negatively received from Island management, leaving the group to write new material, at the suggestion of Island A&R man Richard Williams. After Collins left for Genesis commitments, the line-up changed from Jones, John Goodsall on guitar, Robin Lumley on keyboards and vocals, Pete Bonas on guitar, and John Dillon on drums and percussion, to a departing Bonas and Dillon, the latter replaced by Phil Spinelli for a short time before a newly available Collins took his place in April 1975. The four recorded "Unorthodox Behaviour" in September and October 1975 at Trident Studios with Jack Lancaster on saxophone. They were named Brand X after Island Records staffer Danny Wilding wrote down "Brand X" to keep track of their activity on the studio calendar, and the name stuck. In preparation for their upcoming gigs, the four were joined by Geoff Seopardi on percussion by December 1975. Genesis manager Tony Smith became their manager.