Sir Cliff Richard is suing the BBC and South Yorkshire Police for £1 million over live coverage of a police raid at his home.
The entertainer is understood to have launched legal action alleging there was collusion between the broadcaster and the force that led to the search appearing on television.
Officers investigating allegations of historic sex offences were filmed searching Sir Cliff's apartment in Berkshire in August 2014, leading to him being publicly named as part of the probe. The 75-year-old was never arrested or charged.
The Crown Prosecution Service dismissed the case on grounds of insufficient evidence in June and both the BBC and South Yorkshire Police have apologised to the star.
However Sir Cliff said the "gross intrusion" into his privacy was the result of "illegal collusion" and the fallout damaged his reputation and left him physically unwell.
According to the Daily Mail the £1 million claim reflects damage he suffered personally and commercially as a result of the episode.
It is understood Sir Cliff developed a cough which affected his touring schedule, an album release had to be delayed, sales of his popular calendars were affected and his winery business suffered.
Lawyers are understood to have written to the BBC and South Yorkshire Police to begin the litigation process.
The broadcaster, whose relationship with Sir Cliff stretches back decades, declined to comment. It previously said it was "very sorry" for causing the singer distress.