Thunderbirds creator Gerry Anderson was expected to be one of the star attractions at a new festival celebrating the Sixties in Cromer this weekend.
And fans of the hit TV show were being invited to meet him.
That was until it was pointed out to the event organisers that he died - five years ago.
North Norfolk District Council announced Mr Anderson's impending arrival on its official Twitter account to promote the St George's Day event on Cromer Pier.
And the post was shared on Facebook by local authority cabinet member Angie Fitch Tillett before the gaffe was highlighted.
The tweet read: 'Thunderbirds creator Gerry Anderson is heading to #Cromer60sFestival this Sunday. Come see him! #thunderbirdsarego'
But Thunderbirds fan Richard Leeds, lifeboat operations manager at Cromer RNLI, which is based on the pier where the event will be staged, was quick to spot the mistake.
He said: 'Thunderbirds was one of my favourites, especially for the technology in those days. However, you are going to be clever if you can get Gerry Anderson there - he died about five years ago!'
While Mr Anderson won't be there, a collection of photographs and memorabilia dedicated to the Thunderbirds producer, and chart-toppers The Beatles, will be among the attractions at the festival.
Rock The Lobster, a charitable group promoting unseen and unheard musical talent, have also been booked with its members playing songs from the 60s.
And the public are being invited to join in by sharing their memories of Cromer from the 1960s and dressing up in Sixties style on the day.
There will even be a 1960s Happy Hours with beer priced at just £1-a-pint.
When Britannia Ruled The Airwaves – a Celebration of the Sixties' will be held on Cromer Pier and promenade on Sunday, April 23, from 11am to 4pm.
The council admitted its error and deleted the posts but pointed out the 'mostly-free' festival still boasted an exciting line-up.
Cromer councillor Nigel Pearce said: 'It's going to be a great event. We have already had so much interest in it that we are already looking at the potential of holding the festival over two days next year.'
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