Los Angeles (CNN) -- Organizers of a Michael Jackson tribute concert, supported by the late pop star's mother and four siblings, promise they will announce "an incredible line-up very soon" that will include "some of the greatest names in music."
Promoters missed their deadline of Thursday to name the performers for the October 8 show, forcing them to put registration for tickets to the Cardiff, Wales, concert on hold.
"The registration period was put on hold because we want people to know who they are registering to see," Chris Hunt, the head of the British company promoting the concert, said in a message posted online Friday.
The plan had been to announce the acts over a 10-day period following the July 25 news conference in which Jackson brothers Marlon, Tito and Jackie, sister La Toya and family matriarch Katherine Jackson endorsed the "Michael Forever: The Tribute Concert."
The Global Live Events chief promised fans Friday the process would get on track.
"Between now and October we will be continuing to add names to the line-up so more announcements will follow," Hunt said. "Fans of Michael's music will get the concert they've been waiting for."
"Some of the greatest names in music are already signed, and more are trying to shuffle other commitments to come on board," a statement posted Friday on the concert website said.
Plans for the show appeared to be in disarray Thursday when tickets were to go on sale, but instead of providing a link for purchases the promoter's website asked fans to "Please Standby for further announcements."
The problems started soon after the family announced the "Michael Forever: The Tribute Concert" at the Beverly Hills Hotel on July 25.
La Toya Jackson said it was "something that's spectacular" while the Jacksons' mother called it "a show fit for a king."
"If my son were here today, he would feel the same way," Katherine Jackson said.
"I know my brother would be very, very proud to see all the artists that he admired and respected so much coming together for this event," Tito Jackson said.
But an hour later, Jermaine and Randy Jackson, the only brothers not at the news conference, issued a sharply worded statement that reflected a deep division within the Jackson family over the show. "We want to make clear that this does not reflect the position of the entire family," the two brothers said in a joint statement.
"While we wholeheartedly support the spirit of a tribute that honors our brother, we find it impossible to support an event that is due to take place during the criminal trial surrounding Michael's death."
The involuntary manslaughter trial of Michael Jackson's physician, Dr. Conrad Murray, begins in September and is expected to continue into October.
While Hunt had hinted it could include a Jackson brothers reunion, the statement from Jermaine and Randy Jackson made it clear that would not happen.
"In light of this, we feel it is inappropriate to be involved with such an ill-timed event and its promoter, Global Live," Randy and Jermaine Jackson said. Their statement said the idea of the October concert was presented to the entire family in April "as an idea already in its advanced stages." The decision to go ahead with it "disrespects opinions and wishes expressed in the strongest terms" by some members of the Jackson family, they said.
The Michael Jackson Fan Club agreed with the two brothers, issuing a similar statement. "We share their concerns that this concert is taking place at a most inappropriate time when everyone's care and attention should be focused on the matter of justice. We believe that, as stated by Jermaine and Randy, the most important tribute we can give to Michael Jackson at this time is to seek justice in his name."
Jackson fans posted messages on the concert's Facebook page questioning ticket prices and the process for buying them.
Fans must place bids for a chance to buy a ticket. The higher their pledge to a charity, the better their chances of getting a good seat.
"The ticket system is so bad!! the higher you bid the better seats you get?? not every Michael fan is rich!!!" one fan posted on the "Michael Forever Tribute" Facebook page Thursday.
The October 8 show, in the Wales Millennium Centre in Cardiff, which seats 75,000 people, would be at least four hours long, Hunt said.
In addition to the other problems surrounding the event, a spokesman for Michael Jackson's estate said last week that the promoters never sought or obtained permission from the estate's executors to use late pop singer's name or image.
"The estate has not been contacted and is not involved with Global Live Events in the UK tribute concert announced today," spokesman Jim Bates told CNN.