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

Here's a look at what some are saying:

"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 humour 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.

"George Martin was a gentleman above all. May he rest in peace. Our thoughts are with Judy & the family at this sad time" -- George Harrison's widow Olivia and son Dhani.

"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.

"So sad to hear about Sir George. It is the end of a wonderful era. I had the privilege to have known him as a friend and work with him as an artist. He was a delightful, brilliant man. We won't see his like again" -- musician Elton John on Instagram.

 

"In an era where the words LEGEND and ICON are used far too frequently, there is now one less REAL LEGEND and ICON in the world. George Martin impacted music with contributions that will outlive us all. Sir George, WE Thank you" -- rockers Bon Jovi on Facebook.

"How very sad to wake to the news Sir George Martin has left us. He made my first Bond film sound brilliant!" -- James Bond actor Roger Moore on Twitter.

"Always, always positive, and deeply thoughtful and creative, the man was a gentle giant of popular music" -- Queen guitarist Brian May on his blog.