Coverdale’s status as a member of Deep Purple was cemented by his first public performance. The debut of the Mark III lineup took place on:

When Did David Coverdale Join Deep Purple? The Story Behind the Audition

Coverdale undergoes live auditions and is officially hired.

He was brought in to replace the departing Ian Gillan, who had left the band following the massive Who Do We Think We Are tour. Gillan was exhausted, the band was fighting internally, and Deep Purple needed a new voice to carry them into their next chapter.