The wedding planner in charge of the nuptials of Catherine Zeta Jones and Michael Douglas said yesterday the couple went to extraordinary lengths to prevent the media infiltrating the event.

Simone Martel told a High Court judge that security arrangements for the £1.2m ceremony in Manhattan involved three private-sector companies, the New York Police Department and the city's fire department. The event planner, whose job included tracking down and hiring a Welsh male voice choir from Pennsylvania, was giving evidence in the film stars' breach of privacy claim against Hello! magazine.

Speaking via a video link from America, Ms Martel said the operation to prevent photographers entering the Plaza Hotel involved coded cards for guests and a requirement that all participants sign a confidentiality agreement. She told Mr Justice Lindsay: "We worked on the basis that paranoia is the mother of survival and tried to plan for as many contingencies as possible."

Ms Zeta Jones, who was born in Swansea, and her husband are suing Hello! for £500,000 after covert pictures taken by a paparazzo who gatecrashed the wedding appeared in the magazine within 48 hours of the event in November 2000. Three days before the wedding they had signed a £1m deal with OK! magazine, Hello!'s arch-rival, to provide official pictures of the nuptials. OK! is seeking £1.75m in damages from Hello!

Ms Martel said she had set out to meet the stars' wish that their wedding be "personal, romantic, intimate and unforgettable" as well as free of unwanted visitors.

To keep the event private, entry cards carrying a secret code and stamped with invisible ink were delivered by hand to guests in New York or by courier to those elsewhere.

Guests had to check in for the ceremony, where their cards were scanned. But the measures, including scanning rooms for concealed recording equipment an hour before the ceremony, were to no avail, Ms Martel said. "Despite the enormous levels of security and despite our very best efforts, we now know that our security arrangements were violated."

Undeterred by the court action, Hello! has put the actress on the front cover of its latest issue, published yesterday. In a saccharin interview publicising the musical Chicago, Ms Zeta Jones talks about motherhood and marriage. She also reveals, apparently without irony, that her son Dylan, aged two and a half, is a "genius". She said: "I don't mind telling you that Dylan, well, is a genius. For instance, he has what is called 'perfect pitch'."

The hearing continues.