King Charles III during the Accession Council at St James s Palace, London, Saturday, Sept. 10, 2022, where he is formally proclaimed monarch. AP
Buckingham Palace said the event on November 4 would gather over 200 "international business leaders, decision makers and NGOs" two days before the summit begins in Egypt.
The Palace said the event was to mark the end of the UK's hosting of COP26.
Charles has long backed environmental causes and spoke at the COP26 event in Glasgow in 2021.
But Downing Street said Friday that the monarch will not go to COP27 after the previous UK government led by Liz Truss advised him it was not the "right occasion" for him to attend.
British PM Rishi Sunak has also decided not to go, instead focusing on domestic issues.
The UK's COP26 Minister Alok Sharma told The Sunday Times that he was "pretty disappointed that the prime minister is not going", saying attendance would send a signal about the UK's "renewed commitment on this issue".
The Sunday Times reported earlier that Charles was expected to host an event with Sunak set to make a speech.
Egypt has expressed disappointment that King Charles will not attend COP27, and said it hopes the UK will not backtrack from the global climate agenda.
Addressing new UK Prime Minister Rishi Sunak, Egyptian chief climate negotiator Mohamed Nasr said on Tuesday that he hopes the economic challenges that the UK is facing “do not lead to backsliding on [climate] pledges.”
In a virtual press briefing, Nasr hailed King Charles as a strong advocate for climate action and a role model in this regard, while expressing hope that he will attend COP27.
The king is a committed environmentalist with a long history of campaigning for better conservation, organic farming and tackling climate change.
COP27 will take place in Egypt's Red Sea resort city of Sharm El-Sheikh from 6 to 18 November.
The Egyptian COP27 presidency has repeatedly called for turning climate pledges into action, urging all countries to rise to the occasion and to not allow the current geopolitical situation to affect climate negotiations.