BRICS members will make a statement on the group's expansion at the August 22-24 meeting, Anil Sooklal, sherpa of South Africa in BRICS, said.
The official added that the planned pronouncement will mark a major change in the world order.
"BRICS has been a catalyst for a tectonic change you will see in the global geopolitical architecture starting with the summit," Sooklal said, adding that its expansion was stoking anxiety and opposition among nations in "privileged positions."
According to the sherpa, representatives from 71 nations have been invited to attend the summit, which is "the largest gathering in recent time of countries from the Global South coming together" to address key global issues.
Last month, Sooklal stated that 22 countries had formally applied to BRICS to join the group as full members.
They were joined on Wednesday by Bolivia, which sent a note to Russia about the country's desire to join the BRICS and announced its participation in the August summit.
A day earlier, another South American country, Venezuela, announced that it had officially applied to become a member of the BRICS format. President Nicolas Maduro noted the "leading role" of BRICS in building a new world and laying the path of multipolarity.
Argentina, Algeria, Iran, Egypt and Bangladesh have also already officially applied to join the group.