Mel Winkler, the voice of Lucius Fox on The New Batman Adventures and character actor on numerous television shows over a 40-year career, has died. He was 78 year old.

Per Deadline, family spokesperson Courtney Benson announced that Winkler passed away in his sleep from unknown causes. Winkler portrayed Lucius Fox, adviser to Batman, in four episodes of The New Batman Adventures in 1997 and 1998. He also voiced Commissioner Henderson on Superman: The Animated Series in 1996 and was Johnny Snowman on the 2001-2003 Nickelodeon animated show Oswald, part of the Nick Jr. programming block.

RELATED: Superman: The 10 Best Episodes of Superman: The Animated Series, According to IMDb

Winkler began acting in theater in The Great White Hope on Broadway in 1968. Thereafter, he balanced theater work with TV and film, including August Wilson's Joe Turner's Come and Gone in 1988. His last theater role was in Neil Simon's Proposals in 1997.

After a year on the daytime drama The Doctors in 1969, Winkler appeared on multiple nighttime dramas and genre shows, including Lois and Clark: The New Adventures of SupermanBabylon 5Star Trek: Voyager, ERNYPD Blue and The Shield. His film credits include Doc HollywoodCoach Carter, and Joppy in the Denzel Washington thriller Devil in a Blue Dress. His last listed TV role was in The Disciple in 2008.

KEEP READING: 10 Ways The New Batman Adventures Changed From Batman: The Animated Series