Fans have begun to gather outside the Staples Center in Los Angeles for Michael Jackson's memorial concert, amid strong police presence.
The free concert, which begins at 10am local time, will feature Mariah Carey, Lionel Richie and Stevie Wonder, the BBC reports.
Concrete barriers have been erected outside the concert hall, where Jackson had been rehearsing a comeback show before his untimely death on 25 June from heart failure.
Other people due to take part in the service include Motown boss Berry Gordy, Lionel Richie, Jennifer Hudson, and Britain's Got Talent finalist Shaheen Jafargholi, who has played the young Michael Jackson in the musical Thriller - Live.
More than 1.6 million people applied for one of the 11,000 passes issued for the event, with an additional 6,500 issued for a screening at the nearby Nokia Theatre.
A total of 8,750 people were chosen at random to receive a pair of tickets to attend the ceremony. But many ticketless fans have arrived in Los Angeles hoping to get into the Staples Center.
The Los Angeles Police Department, trying to avoid a mob scene, have warned those without tickets they will not be able to get close to the venue.
One person who will not be attending is Jackson's former wife and the mother of two of his children, Debbie Rowe.
"The onslaught of media attention has made it clear her attendance would be an unnecessary distraction to an event that should focus exclusively on Michael's legacy," her lawyer Marta Almli said in a statement. "Debbie will continue to celebrate Michael's memory privately."
About 50 cinemas across the US are planning to broadcast the memorial live, for free. It will also be relayed to big screens across the United Kingdom, Australia and Hong Kong.
Meanwhile, Jackson's family will attend a private service - expected to be the singer's funeral, shortly before the memorial.
The family have remained tight-lipped about the singer's final resting place, but police have confirmed that a "private function" will be held at the Forest Lawn cemetery in Los Angeles.