Paul McCartney and the son of the late Beatle John Lennon, Julian Lennon, reunited after running into each other at the airport over the weekend.

Lennon took to Twitter to share two black-and-white photos with the legendary musician.

“It’s amazing who you run into in an airport Lounge! None other than Uncle Paul….” Lennon wrote in the caption. “So, so lovely, and what are the chances… Thankful,” he concluded with a series of sweet emojis.

The first photo shows Julian and his Uncle Paul smiling at the camera and the second photo is of Paul pointing at his phone which has one of Lennon’s new albums Jude pulled up. The September release marked Lennon’s first album in over a decade.

If you’re a fan of the Beatles you probably already know this story, but for those who don’t, one of the legendary band’s biggest songs was written by McCartney for Julian. During a rough period for the band and Lennon’s personal life, after he left Cynthia Powell for Yoko Ono, McCartney wrote the hit song “Hey Jude” to help comfort a five-year-old Julian.

Paul McCartney holds Julian, 4, son of John Lennon (visible in the background) during a holiday in Greece.

The song’s original title was “Hey Jules” and McCartney wrote it while making his way to visit Julian and his mother. “I was touched by his obvious concern for our welfare … On the journey down he composed ‘Hey Jude’ in the car. I will never forget Paul’s gesture of care and concern in coming to see us,” Cynthia once said about the song. McCartney later changed the name in the song to “Jude” because he “thought that sounded a bit better.”