Michael Jackson's ex-wife told jurors that the entertainer was surrounded by "opportunistic vultures" out to take advantage of a man she knew privately to be kind, selfless and "generous to a fault".

The testimony by Debbie Rowe, the mother of Mr Jackson's two oldest children, was a setback to prosecutors who had called her as a witness to link the 46-year-old entertainer to an alleged conspiracy to imprison the family of a then-13-year-old boy who accuses him of sexual molestation.

Mr Jackson, 46, faces charges of holding the boy's family at his Neverland estate and bullying them into making a videotaped interview singing his praises in early 2003, just as his public image was unravelling in the wake of a televised documentary in which he defended his practice of sharing his bed with children.

Ms Rowe, who never lived with Mr Jackson but was married to him from 1997 to 1999, also filmed a nine-hour interview as part of Mr Jackson's public relations effort at the time, but she denied her answers were scripted, contrary to the earlier assertion by prosecutors.

Ms Rowe said she had participated in the video after taking a call from Mr Jackson himself and had hoped to restore a relationship with their children, Prince Michael and Paris.

She surrendered her parental rights as part of her divorce from Mr Jackson and at one point was only able to see the children for eight hours every 45 days.

Ms Rowe, who has since sued and recovered her parental rights, said she had not seen the two children since the interview.

She remains in a court fight with Mr Jackson over visitation rights for her children, but admitted that after so many years, returning to them now as their mother was "complicated."

Mr Jackson has a third child, Prince Michael II, by an unknown mother. "I wanted to see my children and possibly get to renew my relationship with Mr Jackson," said Ms Rowe, who took the witness stand in a dark suit.

But Ms Rowe reserved her anger for Mr Jackson's associates, among them Marc Schaffel, an unindicted co-conspirator in the case against the one-time "King of Pop."

Mr Schaffel, Ms Rowe said, was a liar, who claimed that Mr Jackson owed him a million dollars and who once bragged that he had made $7.5 million from the interview she gave while he was present.

After the interview, she said she had repeatedly called Mr Schaffel to see when she could see her children, but said such a meeting was never arranged.

Mr Jackson, she recalled telling police, was "easily manipulated, especially if he's scared."

"There are different Michaels. There's my Michael," Ms Rowe said tearfully, "and then there's the Michael that everyone else sees."

Mr Jackson, who has pleaded innocent, faces more than 20 years in prison if convicted of all 10 criminal charges against him.

Ms Rowe, who had been expected to be a high-voltage witness for the prosecution, spent only about an hour answering their questions and prosecutors never pressed her to more fully explain what she meant when she said on Wednesday she had lied when she praised Mr Jackson's parenting skills.

Mr Jackson attorney Tom Mesereau first asked Santa Barbara County Superior Court Judge Rodney Melville to strike Ms Rowe's testimony, arguing she had not testified in the way that prosecutors had said she would.

He later withdrew that motion after completing his cross-examination where Ms Rowe praised Mr Jackson.

At one point, Ms Rowe, who said she had not spoken to Mr Jackson since the 2003 phone call, turned to the entertainer to help answer when describing when she had toured together with him. The unusual exchange, in which Mr Jackson nodded in response, drew an objection from prosecutor Ron Zonen and a rebuke from the judge.

She also appeared upset when reminded by Mr Mesereau that police had taped one of their interviews with her.

"You did? You did?" she said turning to prosecutors. "... you guys don't share anything."