John Driskell Hopkins, founding member of Zac Brown Band, has ALS, he says in video

John Driskell Hopkins, a founding member and the bassist for the country music group the Zac Brown Band, says he has been diagnosed with Lou Gehrig's disease.

Hopkins, 51, announced the diagnosis in a video posted to the band's official YouTube channel Friday. He told viewers he had some "tough news" to share.

Amyotrophic lateral sclerosis, or ALS, sometimes known as Lou Gehrig’s disease, targets the nervous system, weakening muscles and limiting physical function.

Hopkins said he had noticed issues with his balance for several years and that his hands would become stiff. He said he met with doctors and that "after careful analysis by some of the country’s top neurologists, I have been diagnosed with ALS."

"Because my symptoms have been slow-progressing from the start," Hopkins said, "we believe they will continue to be slow-progressing going forward."

The video ends with a text line to donate to ALS research and a message to "Hop on a Cure." Hopkins is sometimes called "Hop."

"God willing," Hopkins said, "I plan to be rocking with these amazing people for many years to come.”

The Zac Brown Band is touring, and dates are listed through November, according to its website.