Television presenter Gloria Hunniford has told a court how Sir Cliff Richard seemed "broken" after a BBC raid on his home was broadcast.
The star, who is a close friend of Sir Richard, claimed the BBC's decision to run footage of a police search of his home left him feeling "violated and betrayed" to a High Court judge.
Sir Cliff Richard has sought legal action over the BBC's decision to broadcast footage which was staged after allegations of sexual assault.
Ms Hunniford said she "encountered" a "real emotional and mental change" in the singer following a broadcast of police searching his apartment in Sunningdale, Berkshire, nearly four years ago.
In a written witness statement, Ms Hunniford described fears for Sir Cliff's health after watching the BBC report of police searching his home in 2014.
"I could not believe what I was seeing," she said.
"He (Sir Cliff) is a gentle and kind soul and I was extremely worried about how he would be reacting."
She added: "He seemed utterly distraught that the search and allegations against him had been broadcast so widely around the world, and about what everyone must be thinking about him."
"In my experience, he has always been the most positive and upbeat of people, but speaking to him he seemed like a different person; broken and extremely confused," she said.
"Unfortunately, this impression persisted over the two years that followed. When I met with (him) during this period, I encountered a real emotional and mental change in him, even a physical one."
Sir Cliff told Mr Justice Mann, the judge overseeing his trial, how the BBC's coverage has had a lasting emotional effect, leaving him feeling "forever tainted".
Though the ordeal was very distressing, Ms Hunniford said she had seen Sir Cliff feeling better in recent months.
"He seems more his old self and is looking a lot better," she said.
"However, he cannot stop talking about how violated and betrayed he feels about the BBC decision to broadcast the police search of his apartment and create the media storm that ensued."
The singer has likened the extensive search of his property in Sunningdale, Berkshire, almost four years ago to "watching burglars" tear through his home.
He maintains that the coverage was a "very serious" invasion of his privacy.
Sir Cliff Richard has revealed that he wants damages at the "top end" of the scale, while the BBC claims that coverage of the search was accurate and in good faith.