Brooks & Dunn are done.

Best-selling country duo Kix Brooks and Ronnie Dunn posted a message on their Web site Monday saying they agreed to "call it a day" after 20 years of making music together.

"This ride has been everything and more than we could ever have dreamed ... We owe it all to you, the fans," they said in the message. "If you hear rumors, don't believe them, it's just time."

Brooks & Dunn will release a greatest-hits album on Sept. 8 and tour one last time in 2010.

The duo's many hits include "Boot Scootin' Boogie," "My Maria," "Red Dirt Road" and "Cowgirls Don't Cry" with Reba McEntire.

The men's label, Arista Nashville, said the group has sold more than 30 million albums.

Brooks, 54, and Dunn, 56, were struggling solo artists when Arista's Tim DuBois urged them to join forces in 1990. Together they've scored 23 No. 1 hits.

They've recorded 10 studio albums, the latest 2007's "Cowboy Town."

"They've been to the mountaintop and they've accomplished everything that two human beings joined together musically can do in a career," said Brian Philips, president of Country Music Television. "They've had every kind of hit. Literally, they've explored every musical texture and tempo and style and flavor."

CMT is scheduled to tape Brooks & Dunn performing and discussing their music Wednesday for an episode of the show "Invitation Only" to air in October.

Philips called the announcement of the split a complete surprise. He said he has no idea what they might do in the future, but he's certain it will involve music.

"The guys that I know, I can't imagine either of those two individuals walking away from music. That's unthinkable," Philip said.

The pair steeped itself in the mythical West (the duo's emblem is a sun-bleached steer's skull) and rode the charts with a driving honky-tonk sound. Brooks & Dunn took a turn with 2003's "Red Dirt Road" and often pay homage to their classic rock influences, including playing shows with the Rolling Stones and ZZ Top.

Brooks & Dunn won the Country Music Association's vocal duo of the year award every year between 1992 and 2006, except for 2000.

The CMA named the duo entertainer of the year in 1996.

Other country groups have called it quits only to reunite. The mother-daughter duo The Judds split in 1991 but regrouped to tour and record years later.