In a 2012 interview, Hopkins stated, "I've been composing music all my life and if I'd been clever enough at school I would like to have gone to music college. As it was I had to settle for being an actor." In 1986, he released a single called "Distant Star", which peaked at No. 75 in the UK Singles Chart. In 2007, he announced he would retire temporarily from the screen to tour around the world. Hopkins has also written music for the concert hall, in collaboration with Stephen Barton as orchestrator. These compositions include The Masque of Time, given its world premiere with the Dallas Symphony Orchestra in October 2008, and Schizoid Salsa.
In January 2012, Hopkins released an album of classical music, entitled Composer, performed by the City of Birmingham Symphony Orchestra, and released on CD via the UK radio station Classic FM. The album consists of nine of his original works and film scores, with one of the pieces titled "Margam" in tribute to his home town near Port Talbot in Wales.
Hopkins has been married three times: to Petronella Barker from 1966 to 1972; to Jennifer Lynton from 1973 to 2002; and, since 2003, to Stella Arroyave. On Christmas Eve 2012, he celebrated his 10th wedding anniversary by having a blessing at a private service at St Davids Cathedral in St Davids, Pembrokeshire, in the most westerly point of Wales. He has a daughter, actress and singer Abigail Hopkins (born 20 August 1968), from his first marriage. The two are estranged; when asked if he had any grandchildren, he said, "I don't have any idea. People break up. Families split and, you know, 'Get on with your life.' People make choices. I don't care one way or the other."