LOS ANGELES — As an actor, Harry Lewis took second billing to the likes of Humphrey Bogart and Edward G. Robinson, most notably in the 1948 film noir “Key Largo.”

But he found his own starring role as a Los Angeles restaurateur who helped usher in the concept of the “gourmet burger” when he launched the ground-breaking Hamburger Hamlet restaurant chain, among others.

Hamburger Hamlet — named after one of the signature items on the menu, as well as the role that beckons to actors of stage and film alike — became that rare high-low hit.

Among the restaurant’s regulars: Ronald Reagan, Elizabeth Taylor, Sammy Davis Jr. and Tony Curtis — all Lewis’ buddies from the film business. But it was also a place for Los Angeles families looking for a night out that included milkshakes.