Journalist Dan Evans described to the court Jude Law's reaction to his then-girlfriend's affair with his friend Daniel Craig.
He said: "Jude was obviously bouncing with anger about it. The PR performed a character assassination on Sienna.
"The story was run past the PR in its entirety. She approved it, and Jude approved the story to go in. He was obviously very unhappy at the time."
Yesterday, Law gave evidence to the trial for more than an hour.
He told the jury there was an "unhealthy" amount of press interest in his private life.
The jury were sent home and the trial adjourned until 10am tomorrow.