The Pitch Perfect star is being sued by Charlotte MacInnes, the 27-year-old lead actor of the musical comedy The Deb.
MacInnes alleges she was defamed by Wilson in social media posts that suggested she is a liar who retracted a sexual harassment complaint to further her acting and music career.
The young actor confided she felt uncomfortable after the film's co-producer, Amanda Ghost, asked to have a shower and a bath together in September 2023, according to Wilson.
During her second day in the witness box on Wednesday, the first-time director told the Federal Court MacInnes later "flip-flopped" on her complaint while sounding nervous in a phone call.
MacInnes' barrister Sue Chrysanthou SC noted her client had consistently denied making a complaint and suggested Wilson made up the comments to sow division.
The Bridesmaids star rejected the accusation, and described a producer and young lead actor having a bath together as a terrible scenario.
"It is an absolute nightmare situation for me who's a first-time director making a movie that is essentially a girl-power movie," she said.
"It would not at all be in my interest to make up a sexual harassment complaint."
The pair shared a bath in their swimwear after the producer suffered a medical episode but MacInnes maintains she doesn't feel it was inappropriate.
Wilson alleges someone persuaded the young actor to change her story before the phone call in which she insisted she had not been uncomfortable.
The A-lister reported back to Ms Ghost, telling her "Charlotte says all good" and that the actor had reported "zero issues", texts tendered to the court show.
But Wilson said she felt a lingering sense of unease about the situation after observing a change in how the pair interacted, including overt sexual conversations.
"It was really suss," she said.
Ms Chrysanthou accused the Hollywood star of raising the alleged complaint after it had been resolved in order to get her way during a dispute with her co-producer, something Wilson denied.
She was asked how she had details about MacInnes' international travel movements over the past three years, given she has been blocked by the young actor on social media.
"There's a group of people called the 'I hate Amanda Ghost fan club' and they send me information," Wilson replied.
The group comprises various people who have had disputes with Ms Ghost and used the term "fan club" ironically, she explained.
The actor says she doesn't know who set it up and she is not a member but rather a recipient.
She has repeatedly denied bullying and harassing MacInnes, saying she considers herself a champion of women.
Wilson was questioned about texts she sent to the young star in May 2023 after inviting her to a theatre production with other cast members of The Deb.
MacInnes apologised for not getting back to her and blamed a lack of wi-fi, the texts showed.
"I appreciate the apology," Wilson replied.
"In the future, it is terribly rude to say you wanted a ticket to a show and then you don't reply or follow up ... not a great start to our working relationship."
Wilson rejected suggestions from Ms Chrysanthou that the text was utterly inappropriate, bullying or "over the top chastisement" of a junior actor.
"I don't regard one text message as bullying," she said.
The multihyphenate will return to the witness box for a third day on Thursday.
