Became the lover and longtime companion of actress Vivien Leigh following her divorce from Laurence Olivier in 1960. He also became her dedicated caretaker in her final years as manic depression and prolonged illnesses grew severe. He was by her side when she died of tuberculosis in 1967.
In 1970, he was given ten years to live because of a previously undiagnosed hereditary kidney condition. He fell into a relationship with long-time friend actress Dinah Sheridan, who learned how to administer kidney dialysis at home. They married in 1986 and John died four years later, having stretched his life from ten to twenty years.
Son of Philip Merivale, stepson of Gladys Cooper.
Stepbrother of Sally Pearson.