'Die Hard 2' and 'The Waltons' Actor Tom Bower Dead at 86

Tom Bower -- the actor famous for his roles in "The Waltons" and "Die Hard 2" -- has died.

The longtime veteran character actor passed away from unknown causes at his L.A. home last week ... this according to his brother Robert Bower, who talked to THR. The exact circumstances of his death have yet to be revealed.

Before hitting the big time, Bower studied acting at John Cassavetes Shadows Workshop ... and then spent 15 years as a private investigator before diving into acting in 1972 with "The Basic Training of Pavlo Hummel," alongside Al Pacino.

From the 1982 Western "The Ballad of Gregorio Cortez" to 2009's "Bad Lieutenant: Port of Call New Orleans," Bower's career spanned 5 decades and featured acclaimed gigs across various genres.

Bower truly made his mark with his role in 1990's "Die Hard 2," where his character played a crucial part in helping Bruce Willis' character, John McClane, stop terrorists at the airport. He also gained recognition for his portrayal of Dr. Curtis Willard in "The Waltons."

Other big movies he's been in ... "Nixon," "A Clear and Present Danger," "American Me," "Raising Cain," "Beverly Hills Cop II," "The Negotiator," "Hearts in Atlantis" and many more.

His TV credits are just as impressive -- with roles in "The Office," "The West Wing," "Dallas," "Hill Street Blues," "Murder, She Wrote," "Barnaby Jones," "Kojak" and tons of other classics.

Bower was 86.