Actor Gavan O’Herlihy, perhaps best known for being forgotten as Chuck Cunningham on the 1970s sitcom “Happy Days,” is dead at 70.

Variety reports O’Herlihy’s brother confirmed his sibling died last month in Bathe, England, but gave no cause of death.

O’Herlihy scored numerous roles over the years, including TV appearances on “The Six Million Dollar Man” and “Police Woman” and film parts in “Superman III” and “Never Say Never Again,” but in 1974, he played the brother of central “Happy Days” characters Richie and Joanie Cunningham.

O’Herlihy was replaced as Chuck by Randolph Roberts, then the character just disappeared from the popular sitcom with no explanation from the show’s writers.

Characters that get erased from programs as if they never existed have since been known as victims of “Chuck Cunningham Syndrome.”