Geoffrey Rush has told a judge his "blood ran cold" after seeing a newspaper's publication of allegations he had behaved inappropriately toward a female co-star.
The Oscar-winning actor, who denies the claims, is suing the publishers of Sydney's Daily Telegraph newspaper and its journalist Jonathon Moran for defamation over articles published last year.
He faced reporters and photographers as he entered Sydney's Federal Court for the start of the trial on Monday.
The journalists are pleading truth in their defence.
Documents presented in court say the allegations concern Rush's behaviour toward Eryn Jean Norvill during a Sydney Theatre Company production of King Lear in 2015 and 2016.
Rush made lewd gestures in his co-star's direction, simulated fondling and groping her breasts, and regularly made comments or jokes about her involving sexual innuendo, it is alleged.
He is also accused of touching her lower back under her shirt while they were backstage, and tracing his hand down her torso and across the side of her breast during a scene in which he was carrying her.
Rush attended court alongside his wife Jane Menelaus for the start of the judge-only hearing.
He said he was devastated when he saw the first article – beside a headline of "King Leer" – while his wife and adult son were home.
"I could see how distressed they were which created a great deal of hurt for me," Rush told the court.
"I felt as though someone had poured lead into my head. I went into a kind of, 'this can't be happening.'"
The actor said when the paper ran its second article he felt "distraught by the way the story was running off the rails and didn't seem to reflect anything I experienced".
"My blood ran cold and I went to jelly as I thought this is the beginning of a box set, this story is going to continue and it's wilder than you think, dear reader," he said.
Rush told the court the articles did not relate to the "very strenuous but very cheerful" experience he had while working on the play, and that he felt he and Norvill had shared a "very sparky, congenial rapport".
Rush's lawyer Bruce McClintock told the hearing his client was "a national living treasure".
"As well as giving pleasure to millions, his reputation was stellar, it could not have been higher. No scandal attached to his name," Mr McClintock said.
That changed following the articles, which intended to "smash and destroy my client's reputation", he said.
Mr McClintock accused Moran of including "straight-out, bald-faced" lies in his reporting. Defence barrister Tom Blackburn said this was "not based on any evidence because no evidence has been heard".
The Telegraph intends to use Norvill's sworn statement in its defence and she is expected to testify.
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Rush, 67, won the best actor Oscar in 1996 for his portrayal of pianist David Helfgott in Shine, was nominated for roles in Shakespeare In Love, Quills and The King's Speech, and is also famed for his portrayal of Captain Barbossa in the Pirates Of The Caribbean films.
He received his nation's highest civilian honour, the Companion of the Order of Australia for service to the arts, in 2014.