The actress, who played the iconic Dr Sam Ryan from the first series in 1996 through to the eighth, is due to reappear in the upcoming season following an 18-year break from the character.
WATCH: Are you looking forward to the new series?
Speaking to Radio Times recently, the star confirmed that she will not be reprising her role any further. "No. No more Silent Witness," she said. "This has been so special and gorgeous, and to be a part of this landmark celebration of the 25th anniversary is enough."
The 65-year-old went on to say that it was a "surprise" to be asked back to the show, but called it "pretty gorgeous".
"The team confirmed that it was going to be a very interesting story arc over six episodes, and if I didn’t jump and do it, it would be something I would regret," she explained.
Emilia Fox, who replaced Amanda as the show's lead in 2004, praised the star and said that she had left an "incredible legacy".
Amanda Burton will not be returning to Silent Witness following the 25th series
"When I took on the role, I was assured I would be playing a totally different character to Sam Ryan, not least because there was no way I could ever fill her shoes," the Nikki Alexander actress said.
"It was actually so moving, to follow her as a female lead, and what a way to celebrate 25 years.
"When I was asked if I was OK about it, I said I was thrilled, personally and professionally, to welcome her back."
Fans are eagerly waiting for the return of the series, which follows on from Nikki and Jack's romantic encounter at the end of season 23.
Emilia Fox praised Amanda
Chatting about what fans can expect from the pair, Emilia said: "The kiss begged the question of why these two people who have worked together for so long and love each other and are single were not already having a relationship. It threw up many questions.
"How do friends transition to a relationship? Does that relationship dominate everything? How does it work alongside the job? What happens if it goes wrong? What happens if they are in conflict? The lovely thing is that the audience have wanted Jack and Nikki to be together. It's great that they have invested so much in that relationship."
The series returns with six new episodes on Monday 23 May.
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