David and Victoria Beckham have splashed out on a one-off baby monitor decorated by Damien Hirst for daughter Harper.

The couple are long-time fans of the artist - who is famed for preserving dead animals in formaldehyde - and have reportedly decided to add the one-of-a-kind baby accessory to their growing collection of his work.

While the exact price has not been revealed, the butterfly-covered monitor is believed to carry a heft price tag.

A source said: "It has to be the most expensive baby monitor in history."

Victoria also owns a ￡250,000 pair of high heels decorated by Hirst in the style of one of his "spot paintings", as well as a set of personalised Manolo Blahnik ankle boots, to which he added the note: "Posh boots for a Posh bird."

Art critic David Lee estimates that with the art-loving couple's three paintings and a silver bull's heart given to Victoria by David also taken in to consideration, the entire collection at their Los Angeles home is "worth millions".

He told The Sun newspaper: "The value also goes up because it has hung in the house of celebrities."