Hollywood actor Rebel Wilson has praised her directorial debut as she prepares to defend herself in a blockbuster defamation case brought by the film's star.

The Pitch Perfect star directed, co-produced and starred in The Deb, a musical comedy set in rural NSW, the release of which was delayed due to various legal battles.

She is being sued by lead actor Charlotte MacInnes over social media posts claiming she confided in Wilson that she had felt uncomfortable with co-producer Amanda Ghost.

MacInnes has denied making the complaint to Wilson and said she has been seriously harmed by the older actor's suggestions she retracted the alleged comments in return for a lead role and a record deal.

Wilson praised the film as she entered the Federal Court in Sydney on Monday for the first day of a fiery nine-day hearing.

"I love the movie - The Deb is so cute and amazing," she said.

"Thank you to everyone who's going to the cinemas."

The star wore a smile and neutral tones as she entered the courthouse after flying to Australia from the US over the weekend.

MacInnes claims Wilson's social media posts damaged her professional reputation and created doubts about her trustworthiness before she could even enjoy the benefits of playing her first lead role in a film.

The posts blamed her alleged lies for blocking the film's release and portrayed her as selfishly prioritising her own career over the hundreds of cast and crew who toiled on The Deb, according to her statement of claim.

The up-and-coming actor is seeking aggravated damages for serious harm caused as well as a court order preventing Wilson from repeating the allegedly defamatory claims online.

Wilson accepts in her defence that she uploaded a series of posts which were available to her 11 million followers for 24 hours, but denies that two of the posts were about MacInnes.

The Bridesmaid actor maintains the younger performer complained to her about being uncomfortable around Ms Ghost and claims MacInnes was being untruthful when she denied it.

MacInnes lied to have a positive relationship with co-producers Ms Ghost, Gregor Cameron and Vince Holden, from which she derived significant career benefits, Wilson alleges.

She is set to take the stand in the second week of the Federal Court hearing, along with her pregnant wife.

The internationally acclaimed star is also facing a separate legal battle in the NSW Supreme Court brought by Ms Ghost, Mr Cameron and Mr Holden over alleged breaches of contract and damaging statements.

The Deb premiered at Toronto International Film Festival in September 2024 but had been blocked from wider distribution by the ongoing legal disputes.

The film was released in Australia on April 9, with some local reviews praising it as "joyous" and "filthy, fun, but most of all moving", while another said "many moments fall flat".