LOS ANGELES, Feb. 24 (AP) — Al Viola, a guitarist who worked with Frank Sinatra for 25 years and also played the mandolin on the “Godfather” soundtrack, died on Wednesday at his home in Studio City. He was 87.

The cause was cancer, said his wife, Glenna.

Mr. Viola performed with Mr. Sinatra at concerts, on recordings and in television specials. He is heard on such Sinatra hits as “My Way” and “New York, New York.”

Mr. Sinatra once called him “one of the world’s great guitarists.”

Mr. Viola said in an interview on his website: “What I enjoyed most about working with Frank is that he was unpredictable. When I accompanied him, I couldn’t quite predict where he was going, which made it challenging and exciting. He always surprised me on stage. Although he wasn’t known as a jazz singer, he ad-libbed like one and wouldn’t sing a song the same way twice.”

The two first met after World War II in Los Angeles, where Mr. Viola was performing with the Page Cavanaugh Trio. He quit the group in 1949 and became a studio musician. In addition to “The Godfather,” he is heard on numerous television and movie soundtracks, including “West Side Story” and “Blazing Saddles.”

He also appeared on more than 500 albums for artists like Neil Diamond and Marvin Gaye.

“He was a chameleon and could play in any style — that was his great talent,” the jazz singer Judy Chamberlain said.

“He was a flawless player,” she said. “You could barely see his hands move, he was so smooth and quick with his fingers.”

Mr. Viola was born in Brooklyn in 1919 to a musical family and learned the guitar early.

“My brother, who played mandolin, needed someone to accompany him, so he taught me a few chords on guitar to play behind him,” Mr. Viola recalled.

As a youngster, he teamed up with a violinist friend to perform at local Chinese restaurants.

“My mother thought I was robbing the bank because I was bringing home $22 a week during the Depression,” he recalled.

He was in an Army band while stationed in Sacramento during World War II.

His last performance was in late January at a jazz supper club in Sherman Oaks, Calif., his wife said.

In addition to his wife, Mr. Viola is survived by his sons, Dan and Jeff, and a granddaughter.