PHOENIX -- Comedian Jerry Lewis' conspicuous absence will not be the only change at the Muscular Dystrophy Association's telethon this Labor Day weekend.
The Tucson, Ariz.-based organization is making major changes to the telethon, slashing it down from a nearly 22-hour show to six hours of prime-time television in an effort to boost audience numbers, raise more money, and make sponsors and celebrities happy.
The association announced many of the changes Thursday as it moves on from a 45-year partnership with Lewis.
The 85-year-old Lewis and the association still haven't said why they've parted ways, but the move doesn't appear to be hindering the group's plans for the Sunday, Sept. 4, telethon.
"While we deeply appreciate everything that Jerry Lewis has done and his enduring legacy for MDA, our show will go on," MDA spokesman Jim Brown told The Associated Press from Tucson. "It's really not in the best interest of MDA ... to discuss publicly details about what Jerry appears to agree with or didn't disagree with."
MDA announced earlier this month that Lewis was no longer its national chairman and wouldn't be on this year's telethon. When pressed by a reporter at the time about his role with the telethon, Lewis said: "It's none of your business."
Lewis later said he would hold a press conference the day after the telethon to clarify his plans.
"I will have plenty to say about what I think is important. And that's the future, not the past," he said.
Candi Cazau, a Las Vegas-based publicist for Lewis, said Thursday that the comedian can't comment about the telethon or his departure from MDA, though it's not clear why. She declined to comment further.
Since 1966, the telethon has lasted 21 1/2 hours, with Lewis at the helm, and has raised more than $1.6 billion.
Now the telethon will begin at 6 p.m. and end at midnight in all time zones. The show, being taped in Las Vegas, will air live only on the East Coast.
Everyone else in the country will watch the telethon delayed, with two eight-minute segments airing live every hour, Brown said.
He said the association has been discussing the much shorter telethon for at least a year but declined to say whether that was a factor in Lewis' departure from the show.
The shorter air time is in response to television affiliates that complained of the telethon's length, and will ensure a prime-time audience for celebrities and sponsors, Brown said.
Among the celebrities that the association said will appear on the show: Celine Dion, Jennifer Lopez, Lady Antebellum, Richie Sambora and Jordan Sparks.
The show will be co-hosted by "American Idol" executive producer Nigel Lythgoe, "Entertainment Tonight" anchor Nancy O'Dell, "The Biggest Loser" host Alison Sweeney, and journalist and TV producer Jann Carl.
"With social media as strong as it is, it's very helpful for top talent to say, 'Look for me at 6:30 in any time zone,"' Brown said. "Talent is a factor because when we got into the overnight hours, it was harder to get the bigger names to perform for a smaller audience. Everyone wants to be prime time."
Oskar Garcia contributed to this report from Las Vegas.
Follow Amanda Lee Myers on Twitter at http://twitter.com/!/AmandaLeeAP .