The Insider.com

Apparently you really do learn something new every day. Today for instance I learned that most of the radio call-ins on Kelsey Grammer’s hit ‘90s sitcom, Frasier, were actually the voices of A-list celebrities. Who knew!? Check out the viral video to hear some of your favorite celebs voice a bevy of callers with various degrees of mental illness.

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While most assumed the show enlisted voice over actors to play Dr. Frasier Crane’s troubled listeners, the show actually had Christopher Reeve, Kevin Bacon, John Lithgow, Matthew Broderick, Ray Liotta, Cindy Crawford, Ron Howard, Bill Paxton, Dame Helen Mirren, Hilary Duff and more reach out to the good Doc.

Camille Grammer's Custody Battle

You can even hear a young Macaulay Culkin call in as a man mocked for his childlike voice, only to be made fun of by Dr. Crane.

For Frasier fans everywhere -- this is sure to be a real treat!