Rachel Zegler was replaced halfway through her performance of Evita at the London Palladium on Thursday (24 July).
The 24-year-old Snow White actor was switched with her understudy, Bella Brown, during the interval of the show, with the change being announced to the audience.
Zegler has earned rave reviews for her performance as Argentine politician Eva Perón in the musical composed by Andrew Lloyd Webber.
A reason for the alteration was not given to audience members. The Independent has contacted London Palladium and representatives for Zegler.

Brown, who played the role of Mistress in the first act, appeared ecstatic at the opportunity as she gushed on an Instagram story on the night: “What a lucky audience getting to see both myself and MY ANGEL REG ZEG!! (sic)”.
“Today really showed just how important swings and covers are within this industry!!” she continued. “They are the pillars of the show!! A proud day to be at @officialevita.”
The production has received widespread attention for Zegler’s performances of “Don’t Cry For Me Argentina” from the balcony of the theatre, in front of members of the public. Brown entered the second half of the show in the same manner.
The performance received six curtain calls and a lengthy standing ovation from the audience, with one person reporting the cast had to take “ten bows” due to the applause.
One fan wrote: “It was amazing seeing Rachel tonight, but Bella Brown was SENSATIONAL. I’m actually glad we got to see her do the second act!”
Another added: “Two performances by two incredibly talented women. Will forever be in awe of all alternates, covers, and swings because you are the ones who keep live theatre alive.”

In a five-star review for The Independent, theatre critic Alice Saville wrote: “Her [Zegler’s] voice has an emotive purity to it that captures the spoilt, childlike quality of the super-rich, too used to adoration to be able to contemplate life without it.
“Zegler beautifully portrays Evita as a natural performer who effortlessly acts her way out of small-town mediocrity, pretending to fall for men who can help her get gigs, then snapping out of it just as fast. When she marries Perón, her new position as the dictator’s wife is the ultimate role.”