According to court documents, Miss Ewen had been cast as Princess Jasmine in the popular musical at the Prince Edward Theatre, in Old Compton Street, from April 2016.
The singer, originally from Plaistow, east London, initially had no problems and claims that issues only began when the original male lead was replaced by West End star Matthew Croke in June 2017.
Her barrister, Tom Nossiter, said the problems arose when singing face-to-face duets – ‘A Million Miles Away’ and ‘A Whole New World’ – with her co-star close to her.
“Matthew Croke found it difficult to keep harmony if he could hear anyone else singing,” said Mr Nossiter. “To compensate for this, during the duets he sang very loudly so that he could not hear the claimant’s voice.
“Mr Croke was six foot one inch tall compared to the claimant’s height of five feet two inches. This meant Mr Croke’s mouth was positioned at broadly the height of the claimant’s forehead microphone when he was singing the duets with her.
“Due to Mr Croke’s very loud singing voice and his position in relation to the claimant’s microphone, during the duets his voice was picked up by the claimant’s microphone.
“This caused the claimant’s voice to be ‘drowned out’ so that she could not hear herself when singing at a volume which was comfortable for her.
“The claimant was forced, repeatedly during the eight performances per week, over a period of about 18 months, to sing at a louder volume and with greater strength than was comfortable and/or safe for her.
“Her vocal cords were placed under strain, increasing the risk of damage being caused to her vocal cords.
“Further, there was something of a vicious circle in that the louder she sang, the louder Matthew Croke sang over her.”
Mr Nossiter claimed that Miss Ewen complained on “many” occasions about the sound mix on stage and being drowned out, but was told to “sing louder.”
“From about March 2018, the claimant began to experience symptoms of recurrent hoarseness, discomfort and imbalance in her singing voice,” he said.
“To be able to perform satisfactorily in the shows, she started having to take enforced breaks from speaking and singing and to spend her days off in complete silence.
“Thereafter, she experienced an acute event while singing when she felt a ‘pop’ and the quality of her voice subsequently had a ‘cracking’ or ‘frying’ sound to it and she was unable to reach her upper register.”
She tried to continue performing with vocal warmups and using a nebuliser, but in January 2019 sought medical treatment and did not perform in the show again.
“The damage was successfully treated by two surgical procedures during 2019 and the prognosis is good, so long as the claimant adheres to good vocal hygiene and avoids working in unhealthy acoustic environments again,” said Mr Nossiter.
“She also suffered from anxiety and panic symptoms around her voice and career, which have abated since successful treatment.
“She has suffered a psychological reaction in that she experiences anxiety regarding performing in roles in musical theatre as a result of the aforesaid injuries.
“This has caused her to turn down offers of lucrative contracts in musical theatre, resulting in significant loss of earnings.”
Miss Ewen’s lawyers claim that Disney was negligent in failing to undertake an adequate risk assessment and failing to make sure the sound system was suitable.
Her bosses also failed to act on her complaints and should have provided in-ear monitors so she could hear her own voice, it is claimed.