Crowds are gathering to catch a glimpse of pop legend Michael Jackson before his Oxford Union speech about his children's charity.

The pop superstar is the latest in a long line of political leaders and celebrities to speak in the 178-year-old university debating institution.

He is going to speak about balancing love and family and his charity, Heal the Kids, and will be joined by its co-founder, Rabbi Shmuley Boteach.

The move by Jackson, who rarely utters more than a few words in public, is seen by many as a bold one as eight years ago he faced child abuse allegations.

Jackson arrived at Monday's book launch carrying a picture of a child

He was never charged and has always vigorously denied the claims, settling out of court for an undisclosed sum.

So far about 150 fans have gathered, and 300 fans from Jackson's Munich-based fanclub Angel told BBC News Online: "We are travelling to London after this to show our support for him - he's the greatest arist on earth."

They are not the only ones - a Michael Jackson impersonator has been silently walking around the area where the fans are gathering, choosing to soak up the atmosphere rather than say why he is there.

But not everyone is pleased with Jackson's presence at the union.

Oxford is one of the UK's oldest universities

Reverend David Johnson, a former standing committee member of Oxford Union, told BBC News Online: "It's disgraceful, it's brought the union into disrepute.

"I've met senior people who won't speak here because they've had the likes of OJ Simpson and Kermit the Frog speaking here.

"It's been turned into a travelling circus."

Jackson has promised that his speech, which will begin at 2000 GMT, will "surprise the world".

Rabbi Boteach agreed, saying: "It's about getting parents to enjoy their children and put them first.

The UK press is unlikely to get close to Jackson

"It's an incredibly inspiring message which he's going to deliver. And people should stay tuned."

But at Jackson's Neverland ranch in California a nanny brings up his own two young children. He and their mother are divorced, but his partners defend him.

Uri Geller, a friend of the singer and the rabbi, said Jackson had good cause to publicise and help with the Heal the Kids, adding: "He is such a loving parent. I don't see any reason why he shouldn't be involved with such a charity."

Book promotion

Jackson, Rabbi Boteach and Geller were greeted by screaming fans and scores of photographers as they arrived at the Royal Institute of British Architects in central London on Monday night.

The trio were promoting Mr Geller and Rabbi Boteach's book, Confessions of a Rabbi and Psychic - a collection of letters between the two men.

Boteach was introduced to Jackson by Geller.

More than 20,000 people have applied to witness Jackson's Oxford lecture, although only 500 will be allowed into the debating chamber itself.

Reporters will also be kept away from Jackson's address at the Oxford Union.

Geller's marriage vows

A select number will have to make do with watching a video feed of the lecture from a nearby building.

Jackson and the Rabbi both led a conference on their Heal the Kids charity in New York three weeks ago.

Heal The Kids' board members include former Israeli Prime Minister Shimon Peres and actress Elizabeth Taylor, a close friend of the singer.

Jackson's other British engagements include Uri Geller's renewal of marrige vows on Wednesday and a fan club event at the Hammersmith Apollo, west London, later the same day.