In April, an extraordinary auction will provide an unprecedented look into the private world of Michael Jackson. More than 2,000 items, ranging from personal effects and costumes to pieces from Jackson's private art collection as well as fittings and furnishings from his Neverland ranch, will be up for sale at a four-day public auction at the Beverly Hilton hotel in Los Angeles.

Given the continuing fascination that the self-styled King of Pop exerts over the public imagination, Darren Julien, the affable Los Angeles-based auctioneer of celebrity merchandise who is directing the sale, expects a media circus to descend on the hotel as well as tribes of devoted Jackson fans from all corners of the globe. Select lots are to be sent on a touring exhibition that will arrive in Dublin and London in March before a full-scale exhibition opens for one week in Beverly Hills prior to the sale.

The idea, Julien says, is to create the kind of spectacle with which Michael Jackson has been so often associated throughout his career. This is the first sale that the superstar has sanctioned of his property. Michael took legal action in 2007 to try, unsuccessfully, to halt an auction held in Las Vegas of Jackson family items that had been acquired by New Jersey businessman Henry Vaccaro.

This new auction seems to mark Jackson's severance from Neverland, his Xanadu and a symbol of his success as well as his largesse. The ranch opened as a private amusement park in 1988, with its own zoo and Ferris wheel, roller coaster and bumper cars. It was named after Peter Pan's fantasy island where children never grow up, and for years children would arrive by the busload, invited to play freely in its grounds. But following the 2005 child molestation trial - which saw Jackson acquitted of all charges - the singer never returned to the 2,800-acre property in the Santa Ynez Valley, north-west of Los Angeles. There were stories of him pitching up in Dubai, Dublin and Las Vegas before he started renting a seven-bedroom mansion in Bel-Air, Los Angeles, earlier this year. The 50-year-old star was said to be defaulting on payments on vast loans, and while he is thought to retain an interest in Neverland through his involvement with a private investment company, Colony Capital, he has said that the police investigation of the premises "violated" it in his eyes.

Before it was recently renamed Sycamore Valley Ranch, and at Jackson's request, Darren Julien and his team were brought in to scrutinise the ranch. What they found inside was the most astonishing collection of objects these experienced auctioneers said they had ever seen in a celebrity home. "It seemed as if everything he owned was made of bronze and marble and gold," says Michael Doyle, who catalogued the sale items, as well as determining their value.

Jackson surrounded himself with regal finery. There were suits of armour, display cases of custom-made crowns and an ornately carved throne with red velvet upholstering in his bedroom. "King Michael" even had a royal cape, a Father's Day present inscribed inside with a message from his children "Princess Paris" and "Prince Michael". In the lobby of the house was a commissioned portrait of Jackson as a young man in Elizabethan dress, holding a crown on a velvet pillow. Julien and his team spent almost two months at Neverland last summer, meticulously cataloguing 2,000 items, which will be sorted into 1,500 lots. Cranes and forklifts were brought in to dismantle the fairground rides and move the ornate bronze sculptures scattered across 38 acres of the estate.

In a nondescript warehouse on the outskirts of Los Angeles, the famed gates of the Neverland ranch now sit against a wall. The interior of the warehouse is littered with the ornaments that once decorated the grounds. There are bronze statues of frolicking cherubs, replica marble busts of Roman emperors, a huge statue of Prometheus that used to sit on a skull near the entrance. On shelves there are child-size diesel-powered race cars that used to zoom around the grounds. There is a Pope-mobile-style electric buggy fitted with tinted windows and stereo system. Another buggy has the King of Pop's face painted on its bonnet.

The sale also includes vintage video game machines, as well as Jackson's collection of 18th- and 19th-century art. There are books about Disney, the Three Stooges, Peter Pan and Alfred Hitchcock, as well as a collection of black history books, including the autobiography of Malcolm X. Then there is a selection of his own stage costumes, dating back from the days of the Jackson 5 through to the present. There is one of the fedoras he wore in the video for Billie Jean; a pair of trousers so studded with diamanté that they feel as heavy as chain mail; there are customised military jackets, featuring insignia surely acquired on his global travels - including badges from the Royal Air Force and the Thai Narcotics Bureau.

While the lots are "priced as if you and I had owned them, not as if they were owned by Michael Jackson", according to Martin J Nowlan, the Irish co-owner of Julien's Auctions, this is "certainly not a fire sale" of Jackson's belongings - there is, he says, much more to the singer's hoardings. But it would seem to have a personal significance, perhaps symbolising the point at which Jackson himself feels finally able to divest himself of much that conspired to tarnish his career in order to begin anew.

• This article was amended on Sunday 22 February 2009. We placed Michael Jackson's Neverland estate "130 miles west of Los Angeles", which would put it miles out in the Pacific Ocean. Neverland is north west of LA. This has been corrected.