The ITV series Doc Martin is worth millions to the Cornish economy, according to Visit Cornwall.
The cast and crew are currently in Port Isaac filming series 8 of the hit drama series.
The programme, about a grumpy doctor with a fear of blood is now broadcast worldwide.
The Doc Martin effect has seen a growth in demand for holiday cottages by international tourists.
Up to twenty Doc Martin fans who call themselves 'Clunatics' regularly visit from America to watch the series being filmed.
You can watch Kathy Wardle's full report below: