John Lennon Honored by His Sons, Paul McCartney and Ringo Starr on 40th Anniversary of His Death

It's hard to believe it's been four decades since the tragic death of The Beatles rock legend John Lennon.

On Tuesday — the 40th anniversary of his murder — the 7-time Grammy winner, who was killed on Dec. 8, 1980, was remembered by his children as well as former bandmates Paul McCartney, 78, and Ringo Starr, 80.

Lennon was shot in front of his New York City home, by Mark David Chapman, when he was 40 years old.

In a heartfelt post that McCartney shared on Twitter, the former bassist wrote: "A sad, sad day, but remembering my friend John with the great joy he brought to the world." Added the star, who shared a vintage photo with Lennon that was taken by McCartney's late wife Linda, "I will always be proud and happy to have known and worked with this incredible Scouser! X love, Paul."

Lennon's son Sean Ono, 45, shared a photo of himself along with his older brother Julian, their dad and his own mom Yoko Ono.

The rockstar's elder son Julian, 57, posted a photo of his dad on Twitter. He simply captioned his post, "As Time Goes By...." Also on Twitter, Starr shared a call-to-action in memory of his beloved friend.

"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 [to] sometime today play 'Strawberry Fields Forever.' Peace and love. 😎✌️🌟❤️🎶🎼💝☮️," wrote the drummer.

Born Oct. 9, 1940, Lennon was a British singer-songwriter and peace activist. He became world-renowned for his work as the co-frontman of The Beatles. Lennon and his former bandmate McCartney teamed up to become the most successful songwriting duo in music history. The late icon continued his career as a solo artist after the legendary group disbanded in 1970.

In 1991, Lennon was honored with a Recording Academy Lifetime Achievement Award. He was given the same recognition posthumously in 2014, as a member of The Beatles. In addition to the 15 Beatles tunes that have been included in the Grammy Hall Of Fame, his solo classic "Imagine" — which he recorded with The Plastic Ono Band that he formed with his wife Yoko Ono — was inducted into the Grammy Hall of Fame in 1999.