The Queen will host a reception for international business and investment leaders to mark the Global Investment Summit.
Earlier in the day, the Government will host the one-day summit in London to encourage foreign investment by showcasing the best of British innovation, especially green industries of the future.
The reception comes ahead of the royal family’s attendance at events in Glasgow for the UN climate conference Cop26 in November.
The Department for International Trade has already announced global business leaders and industry heavyweights will join Mr Johnson at the investment summit, with speakers including Professor Dame Sarah Gilbert, one of the Oxford/AstraZeneca Covid vaccine co-creators.
Business Secretary Kwasi Kwarteng will also attend the business summit, which has levelling up and attracting greener and more sustainable investment on the agenda.
The Duke and Duchess of Gloucester and Prince Michael of Kent are also expected at the Windsor reception.