The Supreme Court of Appeal (SCA) in Bloemfontein will hand down judgment in an appeal by President Jacob Zuma and the National Prosecuting Authority (NPA) in the "spy tapes" saga on Friday.
The SCA was now ready to give its verdict after Zuma and the NPA conceded that former NPA boss Mokotedi Mpshe's decision not to prosecute him for corruption charges was irrational.
The ruling will be delivered at 09:30 in Court A.
Zuma and the NPA have approached the SCA seeking leave to appeal the 2016 decision by the North Gauteng High Court in Pretoria.
The 18 charges against Zuma were withdrawn in 2009, just before he was sworn in for his first term as president, but the DA wanted the charges to be reinstated.
In 2016, a full bench of judges overturned the NPA's decision to drop the corruption charges against Zuma that related to fraud, racketeering and money laundering.
Both the NPA and Zuma turned to the SCA after the High Court denied them direct access for an appeal.
But last month Zuma and the NPA made an about-turn and conceded that Mpshe's decision not to prosecute Zuma was irrational.
Advocate Kemp J Kemp, SC, for Zuma, told the full bench of justices that he believed that the NPA had erred in their decision.
"Let's take it a step further - in other words, they made an irrational decision?" Justice Azhar Cachalia quizzed Kemp.
"That is then correct, yes," Kemp replied at the time.
Kemp said that if the SCA finds that Mpshe did not make a rational decision, then someone would have to make a rational decision on that basis.
The long-standing matter was brought by the DA.
Advocate Hilton Epstein, SC, for the NPA, faced tough questions at the time from the visibly unimpressed judges, who pressed him on who had decided on whether Zuma should be prosecuted or not.