Indian Prime Minister Narendra Modi (R) speaks as US President Joe Biden (2L) listens during the first session of the G20 Leaders Summit in New Delhi on September 9, 2023. AFP
The expansion of the bloc is a notable diplomatic victory for Modi, who faces national elections next year and has used hosting rights for this year's forum to burnish his image as an international statesman.
Before his opening speech, Modi greeted African Union chair and Comoros President Azali Assoumani with a warm hug.
"India put a proposal to give permanent membership of G20 to the African Union. I believe that with we have everyone's agreement on this," Modi said in his opening address to the summit.
"With everyone's approval, I request the African Union head to take his seat as a permanent G20 member," he added, banging a ceremonial gavel.
Assoumani then took his seat among world leaders at the invitation of India's foreign affairs minister S. Jaishankar.
The African Union has advocated for full membership for seven years, AU spokesperson Ebba Kalondo said. Until now, South Africa was the bloc's only G20 member.
Finding consensus among members has been increasingly difficult in recent years with deep divisions on the Ukraine war.
"The world has a huge crisis of trust," Modi said in his opening remarks.
"War has made this trust deficit deeper. If we can defeat Covid, we can also conquer this mutual trust crisis."
Permanent G20 membership signals the rise of a continent whose young population of 1.3 billion is set to double by 2050 and make up a quarter of the planet's people.
The AU's 55 member states have pressed for meaningful roles in the global bodies that long represented a now faded post-World War II order, including the United Nations Security Council.
They also want reforms to a global financial system - including the World Bank and other entities - that forces African countries to pay more than others to borrow money, deepening their debt.
The African continent has 60% of the world’s renewable energy assets and more than 30% of the minerals key to renewable and low-carbon technologies. Congo alone has almost half of the world’s cobalt, a metal essential for lithium-ion batteries, according to a United Nations report on Africa's economic development released last month