Sinatra, Jr. died unexpectedly on Wednesday (16Mar16) after suffering a heart attack while on tour in Florida.

Members of his famous family have confirmed the sad news.

Crooner Frank's son had a colourful life - he was kidnapped and held for ransom when he was 19 in 1963, but he escaped his captors and was found walking the streets of Bel Air, Los Angeles. His kidnappers were later convicted.

He worked for years as his father's musical director and conductor, and thrilled sports fans last summer (15) when he performed the American National Anthem at a New York Yankees game.

Sinatra, Jr. was in Daytona Beach, Florida preparing for a concert when he fell ill on Wednesday afternoon.

He was the son of Frank Sinatra and his first wife, Nancy, and the brother of singer and actress Nancy Sinatra and TV producer Tina Sinatra.