Seneca Beaulac on the ABC soap opera after playing The Professor on the original pilot for 'Gilligan's Island.'.

John Gabriel, the actor and singer who portrayed the controlling Dr.

Seneca Beaulac for the first 10 years of the ABC soap opera Ryan’s Hope, has died.

Gabriel’s death was announced on Instagram by his daughter, actress Andrea Gabriel (Lost).

Gabriel portrayed Seneca, chief of staff at New York’s Riverside Hospital, on Ryan’s Hope from 1975 through 1985, then returned as the show was wrapping up in 1988-89.

He appeared on such TV series as Surfside 6, Hawaiian Eye, 77 Sunset Strip and The Flying Nun and worked on Broadway in The Happy Time — as Robert Goulet’s standby — and Applause before landing on Ryan’s Hope

In addition to daughter Andrea, survivors include his wife of 52 years, actress Sandy Gabriel, who played Edna Thornton on ABC’s All My Children; another actress daughter, Melissa; and two grandsons