Courtesy Muscular Dystrophy Association
08/29/2013 at 02:00 PM EDT
grew up watching Frank Sinatra, Elton John and Jerry Lewis perform at the MDA Telethon
. And now the Glee
star will have his
chance to lend his voice to the cause.
"I remember as a kid watching Frank Sinatra sing 'New York, New York' with his orchestra behind him," Morrison, 34, tells PEOPLE. "The telethon is virtually an encyclopedia of what's great in American show business."
The actor and singer says the opportunity to perform at the telethon is "humbling," but also inspiring.
"I don't consider it a challenge, but rather an honor. I'm just excited to be part of a great show for a great cause," Morrison says of the telethon, which will air Sunday (9 p.m. ET) on ABC.
Morrison is just one of the many Hollywood stars slated to take part in the iconic event, including Ryan Seacrest
, the Backstreet Boys, Enrique Iglesias, Paula Abdul
, Austin Mahone and country artists Luke Bryan, Darius Rucker and Lee Ann Womack.
But the truly grew thing about the telethon, Morrison says, is that it keeps the spotlight on the Muscular Dystrophy Association's work.
"The real stars of the show are the MDA families, the kids, who are living with muscle diseases and facing challenges that many of us can barely imagine," he says.
So what exactly will he be singing during the show? "I got my start on Broadway and I'm going to sing one of my favorites songs, from one of the greatest Broadway shows ever," he says.
"That's all I'm going to say, you'll have to tune in to see it."