LOS ANGELES?Tom Bosley, the US actor who played Mr. Cunningham in the hugely popular television series "Happy Days," died Tuesday, his family and agent were quoted as saying. He was 83.

Bosley had parts in a string of shows from the 1960s on including "Marcus Welby MD" and "Murder, She Wrote," but gained international fame as the sometimes grumpy but ultimately understanding father-figure Howard Cunningham.

He was the perfect foil for the show's star the eternally cool Arthur "The Fonz" Fonzarelli played by Henry Winkler, and Cunningham's less hip son Richie, played by Ron Howard.

Winkler voiced sadness, telling Los Angeles's KNX-1070 News Radio: "I'm in shock, I really am. I spoke to him just a few weeks ago and he seemed to be getting his strength back."

"We really were a family. Tom was not only the TV father, he was also one of the dads on the set," he added.

Scott Baio, who played The Fonz's cousin Chachi, paid tribute to Bosley on his Twitter page. "Mr. Tom Bosley will be missed by many," Baio wrote. "He was a great actor, teacher and man."

"Happy Days," also known for its foot-tapping theme tune, revolved around the adventures of the Fonz and his friends, often in conflict with the stern Mr. Cunningham ? although always with a happy ending.

Bosley, who had been battling an infection, died at his home in Palm Springs, California, family members told the TMZ website. Local media cited his agent Sheryl Abrams as saying he died of heart failure at 4:00 a.m.