The MACC has summoned Umno president Ahmad Zahid Hamidi for questioning at its headquarters in Putrajaya on Wednesday.
It is learned that the former deputy premier has been asked to turn up at 10am for his third session with MACC since BN was defeated in the May 9 general election.
In July, Zahid was questioned twice by the MACC on two matters - the use of funds from welfare foundation Yayasan Akal Budi to clear credit card debts and his claim that he met representatives of the Saudi royal family member who purportedly channelled RM2.6 billion into former premier Najib Abdul Razak's personal bank accounts.
Investigators, including the US Department of Justice (DOJ), have alleged that the RM2.6 billion originated from 1MDB.
Meanwhile, Umno supreme council Lokman Noor Adam has called for a gathering outside the MACC headquarters to support Zahid.
"Let us all be present to defend our president, who has become the target of (Prime Minister Dr) Mahathir (Mohamad's) regime.
"Do not let our president (be) alone. Sacrifice just one day to defend Umno's dignity, which is being jeopardised by the authorities.
"Expressing solidarity in peace is not an offence, so fear not to appear," he said in an Instagram posting.
Last week, Lokman had warned that Zahid might face court charges similar to Najib and the former premier's wife Rosmah Mansor.