John Lennon has been honoured on the 40th anniversary of his death.

John Lennon

John Lennon

The music icon was remembered by sons Julian and Sean as well as his former Beatles bandmates Sir Paul McCartney and Sir Ringo Starr on Tuesday (08.12.20), which marked four decades since he was murdered in New York City.

In a heartfelt Twitter post, Paul wrote: "A sad, sad day, but remembering my friend John with the great joy he brought to the world."

Alongside an old photograph of the pair taken by his late wife Linda, McCartney added: "I will always be proud and happy to have known and worked with this incredible Scouser! X love, Paul."

Ringo called on radio stations to play Beatles hit 'Strawberry Fields Forever' as he paid tribute to John.

The drummer wrote on Twitter: "Tuesday, 8 December 1980 we all had to say goodbye to John. Peace and love John. I'm asking Every music radio station in the world sometime play 'Strawberry Fields Forever'. Peace and love. (sic)"

The rockstar's eldest son Julian posted a picture of his father on Twitter, which was simply captioned: "As Time Goes By..."

And Sean shared an Instagram snap of himself along with his father, Julian and his mother Yoko Ono.

Meanwhile, Paul recently revealed that he still finds it "difficult" to talk about John's death and doubts he will ever get over his friend being the victim of such a "senseless" act.

The 78-year-old musician told the New York Times magazine: "It’s difficult for me to think about. I rerun the scenario in my head. Very emotional. So much so that I can’t really think about it. It kind of implodes. What can you think about that besides anger, sorrow?

"Like any bereavement, the only way out is to remember how good it was with John. Because I can’t get over the senseless act. I can’t think about it. I’m sure it’s some form of denial. But denial is the only way that I can deal with it. Having said that, of course I do think about it, and it’s horrible."