George Martin, the Beatles' urbane producer who quietly guided the band's swift, historic transformation from rowdy club act to musical and cultural revolutionaries, has died, his management said Wednesday. He was 90.

"We can confirm that Sir George Martin passed away peacefully at home yesterday evening," Adam Sharp, a founder of CA Management, said in an email.

Former Beatle Paul McCartney said Martin had been "a true gentleman and like a second father to me."

"If anyone earned the title of the fifth Beatle it was George," McCartney said. "From the day that he gave the Beatles our first recording contract, to the last time I saw him, he was the most generous, intelligent and musical person I've ever had the pleasure to know."

Beatles drummer Ringo Starr tweeted earlier: "God bless George Martin peace and love to Judy and his family love Ringo and Barbara. George will be missed."

Too modest to claim the title of the fifth Beatle, the tall, elegant Londoner produced some of the most popular and influential albums of modern times - "Sgt. Pepper's Lonely Hearts Club Band," ''Revolver," ''Rubber Soul," ''Abbey Road" - elevating rock LPs to art forms - "concepts."

He won six Grammys and was inducted into the Rock and Roll Hall of Fame, in 1999. Three years earlier, he was knighted by Queen Elizabeth II.