LONDON (AP) — Musicians, politicians and others are paying tribute to music producer George Martin, who has died aged 90.

"I have so many wonderful memories of this great man that will be with me forever. He was a true gentleman and like a second father to me. He guided the career of The Beatles with such skill and good humor that he became a true friend to me and my family. If anyone earned the title of the Fifth Beatle it was George" — Paul McCartney.

"God bless George Martin peace and love to Judy and his family love Ringo and Barbara George will be missed" — Beatles drummer Ringo Starr on Twitter.

"R.I.P. George Martin. I'm so gutted I don't have many words. Thinking of Judy and Giles and family. Love Always, Sean" — John Lennon's son Sean Ono Lennon on Twitter.

"RIP to my musical brother George Martin. We were friends since 1964, & I am so thankful 4 that gift. Bless u & your precious posse 4ever" — musician-producer Quincy Jones on Twitter.

"Sir George Martin was a giant of music - working with the Fab Four to create the world's most enduring pop music," British Prime Minister David Cameron on Twitter.

"Thank you Sir George Martin: the greatest British record producer of all time. We will never stop living in the world you helped create" — producer Mark Ronson on Twitter.

"The legends are really going home! Visionary producer of TheBeatles, George Martin (1926-2016)" — musician Lenny Kravitz on Twitter.

"George Martin was the Edmund Hillary of music — adventurer, explorer, discovering routes for pop music we have all gratefully trod behind in. He was also a beautiful, gentle man I had the pleasure of chatting to on many occasions. A Giant" —Spandau Ballet's Gary Kemp on Twitter.