In September 1982, 20-year-old Vivian Campbell received a late-night telephone call from bassist Jimmy Bain, who was in London with Ronnie James Dio and Vinny Appice following their departure from Black Sabbath. Bain offered Campbell the chance to audition for Dio's new project the following evening, despite having never actually heard the young guitarist play. Campbell, who had been left to leave school at age 16 and fronted the NWOBHM band Sweet Savage, jumped at the opportunity, borrowing money from his father for a return flight and his Gibson Les Paul as his only luggage.

Campbell was primed for his shot at stardom after Sweet Savage, whilst backed by Thin Lizzy on tour, had failed to gain significant traction in the Belfast music scene. At just 20 years old, the guitarist from Magheragall was determined to make his mark, with Campbell himself admitting he was "absolutely ready" when the audition call came. Though Bain had only put Campbell's name forward based on reputation and had never personally witnessed his guitar skills, the young Irish musician would head to John Henry's rehearsal rooms in North London to audition before Dio, Appice and Bain himself.