Two British lawyers, Steven Kay and Gillian Higgins, have been appointed to defend former Yugoslav leader Slobodan Milosevic at The Hague's UN tribunal.
Milosevic is not expected to co-operate with his new lawyers
They are "friends of the court", named at the start of the case to ensure Mr Milosevic would get a fair trial.
The tribunal had said it would impose a lawyer after tests showed Mr Milosevic was not fit to represent himself.
Mr Milosevic is on trial for genocide, war crimes and crimes against humanity in the Balkans in the 1990s.
Steven Kay QC and his assistant will take over Mr Milosevic's case from next Tuesday, when his first defence witnesses are due to be called.
They are neutral observers, known as "amici curiae", who can challenge the prosecution and cross-examine witnesses.
They had previously argued that appointing a defence counsel would be wrong and might even give Mr Milosevic grounds for appeal, should he be convicted, says legal affairs analyst Jon Silverman.
Began February 2002
Milosevic faces more than 60 charges
Prosecutors' case rested February 2004
Court already heard from 295 witnesses
It is not clear how the division of labour will work between Mr Milosevic and his new lawyers. The judges said they would issue an order later to set out the further conduct of the trial.
Mr Milosevic could still name a lawyer of his choice and he could remain actively
involved in conducting his defence, the judges and prosecutors agreed.
Mr Kay said earlier on Thursday that the appointed lawyer would have to base his work on the preparations and witness list that Mr Milosevic had already made.
"The scale - it doesn't get bigger than this," he said.
Mr Milosevic had represented himself since the beginning of the trial in February 2002.
He suffers from high blood pressure and heart problems. His frequent bouts of ill-health have caused months of delay to the trial, which has been interrupted more than a dozen times.
Doctors say his heart condition could become life-threatening if he continues to represent himself.
Prosecutor Geoffrey Nice said Mr Milosevic was "manipulating this tribunal" with his health problems.
Mr Milosevic called the ruling illegal and said it deprived him of his right to represent himself.
"This is highly improper," Mr Milosevic said. "You do not take away somebody's right to self-defence when he is sick."
Mr Milosevic is not expected to co-operate with any counsel appointed against his will.
The judges said they recognised Mr Milosevic's right to represent himself, but said the right "is not unfettered".
The court prefers to speak of "assigning" counsel rather than use the word "imposed", which are legally different terms.