Sir Elton John's ex-wife, Renate Blauel, has launched legal proceedings against the singer at the high court. Blauel filed the legal paperwork last week and is seeking an injunction against her former partner. However, the reason for the legal action is unclear.
Sir Elton is named on the court papers, with Blauel's lawyer saying she is "hoping to resolve it amicably".
The German-born sound engineer met The Rocketman singer while he was recording his comeback album Too Low for Zero in 1983. They married the following year while on tour in Australia. The relationship ended in divorce in 1988, with Sir Elton later announcing he was gay.
He went on to meet his future husband, David Furnish and married him in 2005 after a 12-year relationship. The pair have two sons together.
German-born Blauel has rarely been heard from in public since the split. She has remained fiercely private about the divorce, although there was renewed interest in her relationship with John after it was briefly depicted in last year's biopic Rocketman.
In the autobiography, Sir Elton spoke about agony at his divorce with Blauel and his struggle to accept his sexuality.
"I'd broken the heart of someone I loved and who loved me unconditionally, someone I couldn't fault in any way," he wrote. "Despite all the pain, there was no acrimony involved at all. For years afterwards, whenever something happened to me, the press would turn up on her doorstep, looking for her to dish the dirt, and she never, ever has: she told them to leave her alone."
In the book he said he had very limited contact with Blauel following the separation. "I saw her once after we divorced ... When I had children, I invited her to [John's home] Woodside because I wanted her to meet them; I wanted to see her, I wanted her to be part of our lives, and us part of hers, in some way," he wrote. "But she didn't want to, and I didn't push the issue. I have to respect how she feels."