If the music business was looking for a new comedy double act to rival Ball & Boe, it might just have struck lucky. Sheridan Smith and Amy Wadge are a riot together: swapping compliments, sharing embarrassing stories and finishing each other’s sentences with the warmth of lifelong friends.

You’d never guess, then, that the distinguished duo were strangers until the spring of 2018, when they were thrust together by East West Records A&R exec Paul Samuels to pen Smith’s upcoming ...