The first and deputy first ministers are expected to meet King Charles on Wednesday.
It will form part of a visit to Windsor Castle by executive ministers along with the leaders of the other devolved nations.
The prime minister is also set to take part in the event, which will include a dinner in the evening and continue on Thursday.
First Minister Michelle O’Neill last met King Charles when he visited Northern Ireland in 2022, following the death of his mother Queen Elizabeth II.
