It's hard enough to wrap our heads around the fact that John Lennon was killed nearly 40 years ago. Now another fact to make our jaws drop: He would've been 80 years old Friday. And as tributes circulate on the internet, one "heartfelt message" in particular is gaining lots of attention, per Yahoo: a black-and-white photo posted by former Beatles bandmate Paul McCartney. "I love this picture, it reminds me of the bond between us," McCartney says in his caption accompanying the pic, which shows the two smiling as McCartney jots something on a piece of paper. "Happy 80th John. Love Paul." Lennon's widow, Yoko Ono, also paid tribute to Lennon, putting up a pic of the Empire State Building illuminated blue with a white peace sign to commemorate the occasion. "HAPPY BIRTHDAY JOHN! It's lit!" she posted.
Billboard notes that McCartney and actor Alec Baldwin will be "taking over" SiriusXM's Beatles channel on Friday starting at 11am ET, with their original programming dedicated to Lennon repeating over the weekend and throughout next week. Lennon and Ono's son, Sean Lennon, will be a guest DJ. "It's lovely to think he would have been 80," the 78-year-old McCartney told Baldwin in a preview. "And, you know, that's nice to imagine him at 80. ... I think he would be very literate. I think he would be writing, not necessarily just music 'cause he was starting to get into, he did a couple of little books. I think he would have matured nicely." (Read more John Lennon stories.)