John Lennon's son Julian Lennon reveals medical diagnosis as he urges fans: 'Get checked out!' John Lennon's son, singer-songwriter Julian Lennon, 63, has been diagnosed with coronary heart disease (CHD) and as a pre-diabetic, and he has urged fans to "get checked out sooner than later" in case 13 May 2026 John Lennon's son Julian Lennon has been diagnosed with coronary heart disease (CHD).