Some come to it through the soundtrack, some through hearing ‘Defying Gravity’ sung on Glee, some through seeing the show itself in New York, London or the myriad other cities it has visited. But however fans arrive at the Wicked altar, they worship long and hard.

Maybe it’s the songs, which journey between addictive catchiness and tear-jerking poignancy. Or the on-stage vocal talent those numbers demand; the witty lines peppered throughout the text. It’s most certainly the storyline, cleverly interwoven with The Wizard of Oz, giving its characters a back-story, and gently forcing us to see life differently.

But that’s the audience point of view. What’s it like for those delivering the onstage magic each night? ‘It’s so iconic and well-known, that you do feel a massive responsibility, especially to the fans,’ says Emily Tierney, who plays Glinda. ‘The fanbase of Wicked is like no other show I’ve ever known.’

Playing ‘good witch’ Glinda, opposite the green-skinned and supposedly ‘wicked’ Elphaba, Tierney’s character first appears on stage in a giant ‘bubble’: just one example of the impressive large-scale staging Wicked is known for. ‘It’s the first time the show has toured the UK,’ says Tierney. ‘And I think some people expect it to be less of a spectacle than the West End production, or pared down in some way. But we’re all so proud that this show is of exactly the same standard; we take ten massive trucks with us, and haven’t lost any of the bells and whistles.’

King’s Theatre, Glasgow, Tue 6–Sat 31 May.