Conrad Bain, a veteran stage and film actor who became a star in middle age as the kindly white adoptive father of two young African-American brothers in the TV sitcom Diff'rent Strokes, has died.

Bain died Monday of natural causes in his hometown of Livermore, Calif., according to his daughter, Jennifer Bain. He was 89.

The show that made him famous debuted on NBC in 1978, an era when television comedies tackled relevant social issues. 'Diff'rent Strokes' touched on serious themes but was known better as a family comedy that drew most of its laughs from its standout child actor, Gary Coleman.

(MORE: Diff'rent Strokes Actor Gary Coleman Dead at 42)

Bain played wealthy Manhattan widower Philip Drummond, who promised his dying housekeeper he would raise her sons, played by Coleman and Todd Bridges. Race and class relations became topics on the show as much as the typical trials of growing up.

Coleman, with his sparkling eyes and perfect comic timing, became an immediate star, and Bain, with his long training as a theater actor, proved an ideal straight man. The series lasted six seasons on NBC and two on ABC.

In the show's heyday, Bain didn't mind being overshadowed by the focus on the show's children. He praised Coleman and Bridges as natural talents without egos.

But Diff'rent Strokes is remembered mostly for its child stars.