Fox News commentator Alan Colmes has died at age 66. A cause of death was not immediately released, but a family statement that was aired on Fox said that he died after battling "a brief illness."

After starting out as a stand-up comic before finding a career as a radio host, Colmes provided a liberal voice at the typically conservative Fox News.

From 1996 to 2009, Colmes was the co-host, along with Sean Hannity, of the nightly political show Hannity & Colmes on Fox News. Colmes was also a contributor and commentator on other Fox News programs, including The O'Reilly Factor, Fox News Watch and The Greg Gutfield Show, where he provided the voice of the robot The Liberal Panel. He was also the host of the Fox News Radio show The Alan Colmes Show.

The cable channel announced Colmes' passing via Twitter Thursday morning.

Colmes, also a published author whose books included Red, White & Liberal and Thank the Liberals, is survived by his wife, Dr. Jocelyn Elise Crowley.