Mr Parekh, is one of the first of a network of international ambassadors, that would include high-level business and cultural figures based in London or overseas, a Mayor office statement said.
"As a highly respected Indian business figure, his (Mr Parekh) experience and profile will be invaluable as we build on the excellent relations that we already have with India," Mr Khan said.
Mr Parekh is the chairman of housing finance company HDFC Ltd, a financial conglomerate. He also sits on the boards of a number of companies across diverse sectors.
"I am indeed honoured to be the first International Ambassador with an aim to promote fair and progressive relations between India and London as the city navigates the next many decades," Mr Parekh said.
The role of the 'International Ambassador' will be to "bang the drum for London, promote investment opportunities into London and amplify key Mayoral messages to international audiences", the statement added.
The Mayor announced Mr Parekh as his first International Ambassador at a breakfast in Mumbai with senior business leaders yesterday. Mr Sadiq was in India to promote London as a business and tourism destination and to strengthen the bonds between India and the UK capital.
Mr Parekh is also a member of the City of London's Advisory Council for India which guides the City's engagement with India. In 2010, he became the first international recipient of the Outstanding Achievement Award by the Institute of Chartered Accountants in England and Wales.
The other members of the Mayor's International Ambassadors Network will be announced in the coming months.