The film director Roman Polanski was awarded £50,000 damages after a libel jury found against an American magazine that reported that in 1969 he tried to seduce a Swedish model days after his pregnant wife was stabbed to death in their Hollywood home.
Condé Nast, owners of Vanity Fair, which published the offending article, is understood to now face legal costs of up to £1.5m.
The case had been a massive public relations gamble for Mr Polanski, who spent the first two days of the trial defending his reputation as a serial womaniser and adulterer.
He had to give evidence from Paris by video-link because he feared that if he set foot in Britain he would be extradited to America for a 1978 conviction for unlawful sex with a 13-year-old girl.
Lawyers for Condé Nast, which denied libel, told the High Court in London that Mr Polanski was not only a "fugitive from justice but a fugitive from morality" and that he had little or no reputation to defend.
Mr Polanski called his old friend, the actress Mia Farrow. She told the court the Polish-born film director had been so grief-stricken at the time of Sharon Tate's murder that he was not capable of attempting to seduce the Swedish woman in the famous New York restaurant Elaine's in August 1969 as the magazine had reported.
Mr Polanskisaid it was an "abominable lie" that his arrival in Elaine's on his way from London to Los Angeles to bury his wife, had drawn gasps of astonishment from other diners.
The jury of nine men and three women took four hours to decide that he had been telling the truth when he said that the alleged event did not happen.
Ms Tate, 26, who had been married to Mr Polanski for less than two years, was murdered along with four friends by followers of the Manson "family" on 8 August 1969. Mr Polanski said it would have been an act of "callous indifference to his wife's memory" to have tried to "pull" a woman using Sharon Tate's name .
After the court ruling, Mr Polanski said: "It goes without saying that, while the whole episode is a sad one, I am obviously pleased with the jury's verdict.
"Three years of my life have been interrupted - three years within which I have had no choice but to relive the horrible events of August 1969, the murders of my wife, my unborn child and my friends. Many untruths have been published about me, most of which I have ignored, but the allegations printed in the July 2002 edition of Vanity Fair could not go unchallenged."
He added: "The memory of my late wife was at the forefront of my mind in bringing this action." He also thanked Mia Farrow and Debra Tate, Sharon's younger sister, who gave evidence in support of the claim.
Outside court, Vanity Fair's editor, Graydon Carter, said: "I find it amazing that a man who lives in France can sue a magazine that is published in America in a British courtroom.
"As a father of four children, one of whom is a 12-year-old daughter, I find it equally outrageous that this story is considered defamatory, given the fact that Mr Polanski cannot be here because he slept with a 13-year-old girl a quarter of a century ago."
He added: "Nevertheless it was interesting to see the wheels of British justice move, and I wish Mr Polanski well, and we have a magazine to put out."Reuse content