The season premiere is scheduled for Sept. 10; check local listings for air times.
Season co-hosts will also include Goldie Hawn, Kelly Osbourne, Cyndi Lauper, Howie Mandel, Erin Andrews, D.L. Hughley and Kellie Pickler.
Upcoming guests include Richard Gere, Beyonce, Jake Gyllenhaal, Claire Danes, Meg Ryan, Ben Affleck, Julie Bowen, Ty Burrell, Kerry Washington, Kelsey Grammer, Carol Burnett and Stephen Colbert.
Chenoweth co-hosted twice with Cooper during the chat show's first season and famously surprised a young fan on stage.
Chenoweth won the Tony Award in 1999 for her performance in You're A Good Man, Charlie Brown. She was nominated in 2004 for her performance in Wicked and has also been seen on Broadway in Steel Pier, Epic Proportions, The Apple Tree and Promises, Promises. The actress is also known for her film and television work, including the recent ABC series "GCB."
Her new CD, "Some Lessons Learned," arrived Sept. 13, 2011, on the Sony Masterworks label.