Other stars taking part include America Ferrera, David Cook, Casey Affleck, Meryl Streep, Scarlett Johansson and Kirsten Dunst.
The event will screened on ABC, CBS and NBC on September 4.
Producer Laura Ziskin said: "A lot of us had similar ideas at the same time. And we had some connection with each other.
"Every single person involved in this is touched by this disease in one way or another."
She described the show as "edu-tainment" and also revealed it would feature a cameo from Homer and Marge Simpson.