Charlotte MacInnes has launched defamation proceedings against the Pitch Perfect star over social media posts that claimed she had made a sexual harassment complaint and retracted it to further her career.
MacInnes is the lead actor in The Deb, a musical comedy set in rural New South Wales that was directed and co-produced by Wilson, an Australian.
Her lawsuit against Wilson centres on the aftermath of a medical episode suffered by the film's co-producer Amanda Ghost at Bondi Beach in September 2023.
MacInnes helped her back to an apartment they were sharing with others and the pair ended up sharing a bath in their swimwear in a bid to warm up, she says.
The Bridesmaids star's suggestion she had withdrawn the comment in return for a lead role in a stage production and a record deal has seriously harmed her reputation, she told the court.
The young actor came close to tears during her testimony in the Federal Court on Thursday about the incident and the aftermath.
When she returned to the witness box on Friday, she told the court she felt her evidence had been ridiculed in an Instagram story posted by Wilson's pregnant wife earlier in the day.
The post, seen by AAP, depicted Finding Nemo character Dory with the words: "I suffer from short term memory loss… or do I? I can't remember."
MacInnes' barrister Sue Chrysanthou, SC, suggested the post was referencing her client's responses that she couldn't remember details about four years of travel.
She said the post was relevant to a claim for aggravated damages over the harm caused to the young actor, who attested the post made her feel "awful".
"She was mocking the evidence I gave," MacInnes told the court.
Both Wilson and her wife Ramona Agruma are expected to give evidence in the second week of the legal battle.
Ms Ghost was quizzed on Friday about her support for MacInnes, which included sharing another actor's audition tape to assist her in her own audition efforts.
The young actor previously told the court she was grateful for Ms Ghost's encouragement as she worked hard to achieve her dreams.
She had been confused and deeply distressed when Ms Ghost kept her distance after Wilson aired the actor's alleged complaint.
After she found out the reason for the cold shoulder, the actor said it was important Ms Ghost knew she had never made a complaint.
"If Amanda believed I made an improper complaint against her, I believe that would have very much harmed our relationship," she said.
MacInnes claims her reputation has been seriously damaged by suggestions in the social media posts that she is untrustworthy and prioritised her career over the 300 cast and crew of The Deb.
"(This is) a malignant allegation against my client that she sold the allegation of sexual harassment in exchange for her own professional and commercial benefit," Ms Chrysanthou previously said.
But Wilson denies the posts are defamatory and says the young actor's career has not been adversely affected by the posts.
The key issue is not whether MacInnes was sexually harassed but rather whether she made a complaint and then withdrew it, Wilson's barrister Dauid Sibtain, SC, said.
"Our case is that ... she changed her story," he argued during his opening address.
"She did so to ensure her career as an actress and musician progressed by appeasing Ms Ghost."
