David and Victoria Beckham want to build a "granny flat" in the grounds of their home.

David and Victoria Beckham

David and Victoria Beckham

The couple - who have Brooklyn, 21, Romeo, 17, Cruz, 15, and Harper, eight, together - have submitted an application for a "detached outbuilding" in the gardens of their Oxfordshire abode, and insiders explained the lavish outhouse will be used by guests.

A source told The Sun newspaper's Bizarre column: "David and Victoria want their version of a granny flat.

"But far from this building being on the side of your house with a small kitchen, bedroom and bathroom, they're going all out.

"The fancy building is being built in the same materials as their main house and will have a swanky kitchen, bathroom and bedroom for guests."

It was revealed a few days ago that David and his 46-year-old wife are also hoping to have an underground tunnel from their house to their garage constructed, as well as having a wine cellar installed in the £6 million property.

Planning agents for the property said in submitted documents: "The proposed development includes a new basement cellar constructed beneath the extension to the existing garage outbuilding with a linked walkway.

"The basement cellar beneath is for storage of wine and the proposed use of the outbuilding is solely in association with the main dwelling house.

"It will improve security for the occupants of the property.

"The proposed [garage] extension adds three new bays to the existing garage outbuilding, increasing the building from four bays to seven."

The planned work comes as the latest project for 45-year-old former football ace David, after it was recently revealed he has registered a trademark to protect his name in order to use it for a chain of hotels and restaurants.

A source said: "David is a shrewd businessman and just as he was clever in building brand Beckham with Victoria, he is making sure he protects any future projects.

"He's got his hands full with his team in Miami but his own hotel - that could happen.

"But David won't rush into anything, he'll be making sure any plans to go into the industry are totally watertight before he takes the plunge."