Sir Paul McCartney has marked what would have been the 80th birthday of his late Beatles band mate John Lennon by sharing a black and white photograph of the pair together.
Lennon was shot dead aged 40 in New York in 1980, and has continued to have an enduring influence on popular culture long after his murder.
Sharing a photograph on Instagram, Sir Paul wrote: "I love this picture, it reminds me of the bond between us. Happy 80th John. Love Paul".
Overnight, Beatles drummer Sir Ringo Starr also remembered Lennon.
He posted on Instagram: "Let's celebrate John's 80th birthday with come together Friday, 9 October I still miss you man peace and love to Yoko Sean and Julian."
Yoko Ono, Lennon's wife, posted a short video showing New York's Empire State Building lit up in blue, and with a peace sign, in honour of the day.
Following a chance encounter with his future bandmate Paul McCartney at a church fete in 1957, Lennon went on to change the course of musical history with a body of work which has stood the test of time.
After helping to propel The Beatles to international stardom and securing their place as one of the world's biggest ever bands, he continued to enjoy a varied career.
Following the band's breakup in 1970, the Liverpudlian released his debut solo effort John Lennon/Plastic Ono Band in the same year, which included hits Mother and Working Class Hero.
Less than a year later came Imagine, whose title track has become inextricably linked to his legacy.
The Strawberry Fields memorial to the musician in New York's Central Park, where Lennon's ashes are scattered, features a mosaic bearing the word.
He was also a prominent anti-Vietnam war protester alongside Ono, leading to then-US president Richard Nixon leading a failed three-year bid to have him deported.
Lennon and Ono had their son Sean in 1975 prior to the musician taking a five-year break from music.
His album Double Fantasy, which was recorded with Ono, was released in the year of his death.
Last month, his killer Mark David Chapman, 65, apologised to Ono for his "despicable act", saying that he thinks about it all the time and accepts he may spend the rest of his life behind bars.
He was denied parole for an 11th time following a hearing in August after being jailed for shooting the musician four times outside his Manhattan apartment as Ono looked on.
The occasion is being marked with a pop-up television channel called LENNON80 which will feature special programming to mark his birthday.
It will feature Bed Peace, the documentary charting Lennon and Ono's Bed-In For Peace in Montreal, Canada, in 1969, as well as their 1971 interview on Parkinson.
Universal Music Group is launching the channel on Sky, Virgin and Freeview from Friday until October 15.
His birthday is also being marked in Liverpool, where the council has launched a worldwide contest to find another great songwriter.
A collection of previously unseen pictures of Lennon in New York will also go on display at The Beatles Story in Liverpool.
Earlier this week, Sir Elton John said that if Lennon had lived he probably would have won the Nobel Peace Prize.
Speaking to Lennon's son Sean, who is his godson, to mark the milestone in a BBC Radio 2 special, he said: "I think if your dad had still been alive he would have definitely been, maybe won the Nobel Peace Prize or something.
"That was what your dad was, he wanted to bring people together. He was a uniter and he was prepared to go to any lengths to make people see what his point was."