Tokyo 2020 say the company - the Japanese wing of accountancy firm Ernst & Young - will be a partner in the category of "professional services".

The category covers audit, finance, tax, project management and management consulting.

Tokyo 2020 President Yoshiro Mori claimed the agreement will assist the organising committee as the Olympic and Paralympic Games draws closer.

"We are delighted to welcome EY Japan as an official supporter," Mori said.

"The company has provided various professional audit, taxation advisory and project management services.

"Their further support as experts in these fields will be a major help for the activities of the Organising Committee."

EY Japan are the 18th official supporter of Tokyo 2020, the third tier of the organisation's domestic sponsorship programme.

This includes one official supporter which only sponsors the Paralympic Games.

Tokyo 2020 say the official supporters will have vital roles in the delivery of the Games.

"For the Olympic and Paralympic Games Tokyo 2020, EY Japan is pleased to have the opportunity to provide high-quality professional services involving audit, tax, finance, project management, and planification and management consulting," said Koichi Tsuji, director and chairman of EY Japan.

"Guided by our purpose of building a better working world, EY Japan is truly honoured to participate in the Tokyo 2020 Games as an official supporter.

"We are determined to make the Tokyo 2020 Games an unforgettable experience for people all around the world and are certain that everyone will be able to share in the excitement and joy of these Tokyo 2020 Games."

Organisers also boast 15 gold partners and 32 official partners.

In June, the IOC revealed Tokyo 2020 had achieved in excess of $3 billion (£2.4 billion/€2.6 billion) in domestic sponsorship.

London 2012 was previously believed to hold the record, when $1.1 billion (£866 million/€967 million) was achieved.