Frank Sinatra's former assistant Paul Colby has died at the age of 96.

Colby, who passed away on Thursday (13Feb14), began his career as a song promoter for several music artists, including Louis Armstrong, Duke Ellington and Sinatra, before becoming the My Way crooner's personal assistant.

In 1950, he stepped away from the music industry to open an interior design business, which boasted Tony Bennett and Miles Davis as clients.

He returned to the scene in 1965 as the manager of New York's The Bitter End club, which featured performances from Bob Dylan, Joni Mitchell, Joan Baez, Woody Allen and Billy Crystal. He purchased the venue in 1974, according to DNAinfo.com.

A message on the club's Facebook.com page, reads, "It is with a heavy heart The Bitter End would like to announce the loss of our colonel, Paul Colby, who passed away last night at the age of 96.

"In his 70 plus years in the business, Paul has touched the hearts of countless musicians and patrons and helped to launch many great careers in the music industry."

Colby's death comes a month after Sinatra's entertainment lawyer Donald Engel died at the age of 84 from complications of leukaemia.