Country star Kellie Pickler and 'Good Morning America' co-anchor Robin Roberts have joined a star-studded cast helping the Grand Ole Opry take aim at breast cancer.

On Saturday, Oct. 22, the venerable Nashville music hall will hold its third annual 'Opry Goes Pink' event, staging two special shows in conjunction with the organization Women Rock for the Cure.

Robin will host the first of the shows, which will include a performance from Martina McBride. In addition to singing 'I'm Gonna Love You Through It' -- a tune from her latest album, 'Eleven,' about supporting loved ones stricken with cancer -- Martina will "flip the switch" on the Opry's barn-style backdrop, turning it pink.

Kellie will do likewise during the second show -- a concert that will also feature Lauren Alaina, Edens Edge and Ronnie Milsap -- and as the singer reveals, she has a personal reason for getting involved.

"My grandmother, who raised me and was my angel, died of cancer and I'm honored to participate in every way I can to help bring awareness and raise money to fight this horrible disease," Kellie says.

'Opry Goes Pink' will cap a big week for the 25-year-old former 'American Idol' contestant. Tomorrow (Oct. 19), she'll appear on '90210,' where she'll make her acting debut and sing her latest single, 'Tough.'

Watch a Sneak Peak of Kellie Pickler on '90210'