Champion boxers Laila Ali and Victor Ortiz are fighting back against muscle disease by appearing on the annual MDA Show of Strength Telethon this Labor Day weekend airing Sunday, Aug. 31, 9/8c on ABC television stations across the country.

Ali, former super middleweight world champion and current host of “All In, with Laila Ali," will introduce a performance from American rock band Fall Out Boy during the Muscular Dystrophy Association's nationally broadcast show.

Ortiz will introduce R&B sensation Aloe Blacc’s performance of his hit “The Man.” The former WBC welterweight champ-turned-actor took time from promoting his supporting role in this summer’s blockbuster action flick “The Expendables 3” to show his support for MDA at the Hollywood Palladium.

Both Ali and Ortiz took their support backstage at the show taping to meet with MDA families and learn more about MDA’s mission to save and improve lives of children and adults affected by muscle disease.

“I’ve had to fight a lot of tough bouts in my career to become a champion, but that word - fight - has a whole new meaning for me after meeting with MDA families and learning about the challenges they face every day in the fight against muscle disease,” Ortiz said. “These families are true champions and I’m happy to lend my support to help continue the progress that will one day lead to cure for these life-threatening diseases.”

Ortiz also did an exclusive interview with “blue” carpet correspondent and 15-year-old MDA Ambassador Abbey Umali of Redlands, Calif. Umali is affected by Charcot-Marie-Tooth disease (CMT) which causes muscle weakness, lack of coordination and loss of sensation in the upper and lower extremities. (Click here to see their exclusive interview and learn why Victor Ortiz supports MDA.)

The 2014 MDA telethon will feature a star-studded celebrity lineup with performances from Grammy® winners Rascal Flatts and LeAnn Rimes, plus Aloe Blacc, American Authors, Bret Michaels, Fall Out Boy, Jason Derulo, Matt Nathanson, R5 and Sara Evans.

Additional celebrity presenters on the telethon include: Tom Bergeron, ABC’s Dr. Richard Besser, Jann Carl, Charles Esten, Terry Fator, Kevin Frazier, Josh Groban, Ludacris, Susan Lucci, Kesha, Alyssa Milano, Nancy O’Dell, Brad Paisley, Chris Powell, Jordin Sparks and Fall Out Boy bassist Pete Wentz.