Sir Paul McCartney breaks down in tears every time he hears the Beach Boys' song God Only Knows.
The 65-year-old Beatles legend has confessed he can't control his emotions whenever he hears the Brian Wilson penned track.
Speaking on a special Radio 1 show to mark the British station's 40th anniversary, Paul said: "God Only Knows is one of the few songs that reduces me to tears every time I hear it. It's really just a love song, but it's brilliantly done. It shows the genius of Brian.
"I've actually performed it with him and I'm afraid to say that during the sound check I broke down. It was just too much to stand there singing this song that does my head in, and to stand there singing it with Brian."
During the hour-long show, Paul played a selection of his all-time favourite songs, including The Guillemots' Little Bear, Elvis Presley's Heartbreak Hotel and Beatles classic Hey Jude.
As part of the fortnight-long birthday celebrations, Blondie singer Debbie Harry, Oasis star Noel Gallagher and Gwen Stefani will be taking to the airwaves to host their own hour-long Legends shows.