Catherine Zeta Jones' parents are set to mount a legal challenge over a row about a business being run next to their new £1m Swansea home.
Catherine Zeta Jones' father is worred about security
The star's family opposed the move to allow the firm to continue trading from the exclusive Mumbles estate but it was given the go-ahead.
Her father David Jones has told Swansea Council he may seek a judicial review.
The business could put the security of the Hollywood star and Michael Douglas at risk when they visit, he claims.
Mr Jones said the telecommunications business on the estate, which is protected by security gates, would also infringe on their privacy.
An extra floor is being built onto the house to accommodate the showbiz couple and their children on their frequent trips home to south Wales.
Planning officers recommended the retrospective application was turned down but councillors took a different view.
They heard claims made on behalf of owner Steve Gwynn that star gazers and paparazzi seeking out the actress would create far more of an intrusion.
Councillors said if the Joneses wanted such a high level of security they should have looked for somewhere more isolated - like the Carmarthenshire market town of Llandeilo.
But consultants CDN Planning, representing Mr Jones, have written to the authority stating such claims are "fantasy".
Director Graham Carlisle said: "Claims of minibuses coming to view the site and of helicopters flying over to take photographs are simply not true.
A view from the street into the exclusive Mumbles estate
"(They) are made simply to detract from the very real amenity issues created by the office business run by Mr Gwynn.
"A commercial use of this building can only be a source of potential nuisance to near neighbours.
"This is heightened in this case because it is a gated and highly secure environment, which was chosen specifically by Mr Jones because of the obvious need for security when he receives an occasional visit from his family."
"We have little doubt that our client will immediately seek legal advice regarding a possible judicial review," said Mr Carlile.
Swansea's development control committee passed Mr Gwynn's application on 2 March and it was agreed by full council last week.
A spokeswoman for the authority said she was unaware of any legal proceedings having started.