Abdul's concert is scheduled for April 25.

The series lineup includes Miley Cyrus, Mary J. Blige, Chris Brown, Alanis Morissette, Ashlee Simpson, Kenny Chesney, Coldplay and a "special surprise reunion concert."

Neil Diamond, the B-52s, Donna Summer, Rihanna, Rascal Flatts, Natasha Bedingfield and Sheryl Crow are also slated to perform during the series, which runs through the spring and summer.

Attendance is on a first-come, first-served basis outside "Today's" Window on the World Studio at 49th Street and Rockefeller Plaza in New York, NBC said.