U2 frontman Bono has accused the band's former stylist of blackmail in a court battle to try and stop her selling off possessions they want back.
Bono was at the courthouse in Dublin
Among the items - worth about £3,500 - are a pair of trousers and a hat once worn by the band's lead singer Bono.
Lola Cashman worked for U2 in the 1980s and wrote an unauthorised biography of the band.
Bono hit back at claims they had given items to Ms Cashman as gifts, saying they rarely gave away possessions.
"They sound like trivial items, they're really not. They are important items to the group and we take them seriously," he told the Dublin Circuit Civil Court.
Lola Cashman worked with the band in the 1980s
"You may have wealth and power, but when someone is trying to push us around and blackmail us and threaten us with books, at a certain point you have to say 'Stop right there'," he said.
Bono - real name Paul Hewson - said the band occasionally gave memorabilia, but it would be to charity auctions.
He said he was particularly keen to have his Stetson hat returned because it had iconic status.
"It would be like the Edge (the band's guitarist) giving one of his guitars away. It is not something which will happen," he told the hearing.
He also told the court he had defended Ms Cashman against criticism from band members who had difficulties with her.
But after working with her for two years contract negotiations broke down because her price was considered excessive.
Bono said Ms Cashman had bought trousers of different sizes for him during the Joshua Tree tour.
"Sadly I put on weight all the time. Oscillate is a word you could use," he said.
He added: "It's not particularly embarrassing because it's likely I would fit them again, whether they were a smaller size or a larger size."
The star dismissed suggestions he had been in a euphoric mood after the last date of the tour in Arizona and prepared to give away items to Ms Cashman.
Ms Cashman told the court she had been brought into the tour personally by Bono to help update the band's image and had thought of the Stetsons to give the band a more "raunchy" look.
And the stylist said there had never been any suggestions since she left the band's employ that she had wrongly taken anything.
A former assistant stylist and assistant wardrobe person both told the court they had not been given items.
The court heard Ms Cashman shipped the items to her London home from Arizona where the band had been touring.
U2 are seeking about 200 Polaroid photos which were taken by Ms Cashman as well earrings and a souvenir sweatshirt.
Bandmate Larry Mullen was also at the courthouse with U2 manager Paul McGuinness.
The band recently returned to their home city to perform three homecoming concerts at Dublin's Croke Park, which attracted almost 250,000 people.
U2 are due to take part in the Live 8 concerts on 2 July, playing the London leg of the event in Hyde Park.
The case was adjourned until Wednesday.