Rolf Harris' 90-year-old brother Bruce has dismissed claims his sibling groped a make-up artist so often she dubbed him an "octopus" as a "ridiculous" suggestion.
He gave evidence at Southwark Crown Court via videolink from Sydney, Australia, and said he would have shouted at his younger brother if he had seen him put his hand up the woman's shorts.
Wearing a dark grey suit, lilac shirt and grey tie, he told the court he became the artist and musician's manager in 1981.
He said: "He was unhappy with his management team in the UK. He had fallen on relatively hard times and was not happy with the way they were treating him."
The former advertising boss also took control of his brother's finances.
"Rolf has never shown any interest in the financial side of life," he told the jury of six men and six women.
Rolf Harris is accused of 12 counts of indecent assault on four women between 1968 and 1986, all of which he denies.
Prosecutors have called a number of supporting witnesses who are not named in the charges, including the make-up artist who claimed Harris was nicknamed "the octopus".
The freelancer, who was in her 20s at the time, said he repeatedly put his hands inside her baggy shorts as far as her hips while making a programme in Australia in the mid-1980s.
Bruce Harris said: "That's ridiculous. He would never do that and I wouldn't let him do that, and he knew I wouldn't let him do that. That's just not possible."
Sitting as he gave evidence, he added: "I would have shouted at him, I would have demanded that he stopped. But it never happened, it would never have been something that he would have done.
"I would have taken the elder brother approach to a younger brother misbehaving."
Another alleged victim Tonya Lee, who has waived the usual right to anonymity, claimed Harris touched her intimately when she met him while on tour in the UK with an Australian youth theatre group.
Bruce Harris said the first he knew about the allegations against his brother was when Ms Lee gave a television interview about her claims last year.
He said he called the artistic director of the theatre group, Kathy Henkel, to ask her whether she had seen what allegedly happened.
"In retrospect I kept on niggling away at her, saying 'surely you must have seen something'.
"In Tonya's documentary she went into great detail about what happened over a period of time and I thought that Kathy must have seen something of this. So I kept trying to see. I didn't put any pressure on her.
"I wasn't trying to get her to change her story if that's what you mean, I was trying to see whether she could back up what this girl was saying."
In cross-examination by prosecutor Sasha Wass QC, he admitted that in the "hypothetical" situation that Henkel had supported the claims, he would not have told the police.
He said: "I'm protective of my brother and I also wanted to see if there was any truth to what was being said. I didn't believe it."
The jury has already heard that Henkel could not be certain about what happened on the night of the alleged assault, and that speaking to Bruce she claimed she "felt pressured to say that it couldn't have taken place".
Bruce Harris repeatedly denied trying to influence her, and said if his brother had performed for the theatre group, while they were having dinner together, he would have been most focused on doing his show.
"I can't believe if he had done a show like that he would have had time or been bothered to do the kind of things that Tonya Lee has said," he told the court.
The court then heard from Ken Jeacle, Rolf Harris's former tour manager, who has also worked with acts including comedian Ronnie Corbett, singer Vera Lynn and seventies disco act the Village People.
He began working for Harris in the early 1980s, organising international tours, and said he was "the highest-profile artist in the Australian variety scene" and his profile in his native country was "just indescribable".
The trial was adjourned until tomorrow.