Prince Charles is extending his holiday so he can go fishing.

The 71-year-old royal and his wife Camilla, Duchess of Cornwall, are currently enjoying their annual summer break at Birkhall on the Balmoral Estate in Scotland, and the prince is keen to stay longer than planned so he can pursue one of his favourite hobbies.

Royal photographer Tim Rooke wrote on Twitter: ''I may be having difficulty actually being able to photograph the royals during the pandemic.

''However, out walking the dogs and the Prince of Wales drove past me with fishing rods on his car. Good fishing in this part of Scotland #royals #PrinceCharles #flyfishing.

''Apparently according to a local he has decided to stay up for an extra week because the fishing is so good.(sic)''

Charles may be joined out fishing by his father, Prince Philip - who travelled to Balmoral with his wife Queen Elizabeth earlier this week - because the 99-year-old royal is also known to be a fan of the pursuit and enjoys spending his vacation days catching trout and salmon on the River Dee.

The late Queen Mother was also a fan of the sport, and Charles took over from her as patron of the Salmon and Trout Association.

Charles' wife, Camilla, recently praised her husband as the ''fittest'' man of his age that she knows.

The 72-year-old duchess said: ''He is probably the fittest man of his age I know. He'll walk and walk and walk. He's like a mountain goat - he leaves everybody miles behind.''

Camilla has made the most of not having to get dressed up while she's been out of the public eye and not undertaking in-person official duties but is concerned she'll be very reluctant to stop wearing her jeans when the time comes.

She said: ''It will be very hard to get out of them again. I think you get into a sort of way of life, don't you?''