Beatles producer Sir George Martin, known as the 'fifth Beatle', has died at the age of 90.

FOX's Kitty Logan reports from London:

Tributes have been pouring in for the man who produced some of the best-loved music in modern times, including the most popular Beatles hits:

(The Beatles) "I read the news today, oh boy."

He was pivotal in guiding the Beatles to global success. In a statement, Paul McCartney said George Martin was "like a second father to me" and British Prime Minister David Cameron tweeted his tribute to 'a giant of music.'

Martin had over 50 number one hits in the U.S. and Britain, won six Grammys, and was knighted in 1996.

He also worked with a number of other successful performers in a career which spanned over 70 years.

In London, Kitty Logan, FOX News.