Frank Beard, the longtime drummer for legendary rock band ZZ Top, has died ... TMZ has learned.

According to the Fort Bend County Medical Examiner Frank passed away on August 17 after a stay in hospice. Frank recently faced serious health issues. A cause of death has not been disclosed at this time.

As TMZ previously reported ... Frank's health forced ZZ Top to cancel its August 5 concert at the Hollywood Bowl.

Frontman Billy Gibbons said at the time the band was dealing with "insurmountable obstacles" and asked fans to bear with them during the interruption.

Frank had also been absent from the band's recent performances ... with drummer Michael Monahan filling in behind the kit. ZZ Top performed without Frank in Saratoga, California just days before TMZ learned of his death.

Frank joined ZZ Top in 1969 ... spending more than five decades anchoring the group alongside Gibbons and late bassist Dusty Hill.

He played on all 15 of the band's studio albums and helped power some of its biggest hits, including "La Grange," "Tush," "Gimme All Your Lovin’," "Sharp Dressed Man" and "Legs."

ZZ Top was inducted into the Rock and Roll Hall of Fame in 2004. The group's classic lineup remained intact until Dusty died in 2021.

Frank was 77.

RIP