Examining the request by court-assigned counsel, the trial chamber found the appeal justified because the accused opposed the decision on assignment of defence counsel and expressed his desire to appeal the ruling.
Milosevic did not file a formal appeal, demonstrating that he does not recognise the tribunal.
The trial chamber concluded that the decision to assign counsel "affects fundamentally the conduct of the trial and as such it would be best to have it resolved by the appeals chamber at this stage, rather than after the conclusion of the trial".
Before they were appointed defence counsel by the trial chamber's oral decision of September 2, Kay and Higgins were involved in the trial as "friends of the court".
This week's examination of the first defence witnesses by Kay prompted a stormy response from Milosevic, who said that it had nothing to do with his line of defence and that it was detrimental to his defence.
After one of Milosevic's protests, Kay said in the courtroom on Thursday: "I was not a volunteer."
The newly-developed situation has been further complicated by the decision of some of the already announced witnesses not to appear, who cited as their reason the imposition of defence counsel on Milosevic. Among them were former member of the Russian parliament Nikolai Rizhkov, five French witnesses, including former intelligence service chief Yves Bonnet, three witness from the US State Department, and former Greek prime minister Constantin Mitsotakis.
On Thursday, presiding judge Patrick Robinson called on the witnesses to appear at the tribunal and testify for the defence.
The trial is scheduled to resume next Tuesday.