President Michael D Higgins and his wife Sabina are self-isolating after testing positive for Covid-19.
Aras an Uachtarain said in a statement that they were both displaying "mild Covid-19 symptoms" on Friday morning.
They took antigen tests which subsequently showed positive results and will now be self-isolating for the next week.
President Higgins will work from home while isolating.
A spokesperson said in a statement: "President and Sabina Higgins, having displayed mild Covid-19 symptoms this morning and having taken antigen tests that have tested positive, will be isolating for the next 7 days.
"The President while isolating is continuing to work from home."
President Higgins was due to attend an event in Ballymun on Friday morning before the positive Covid result.
It comes after he issued a powerful statement earlier this week denouncing the actions of Russia following its invasion of Ukraine.
“That we have returned to war, the abuse by the powerful of its neighbour, the flagrant violations of the principals of the United Nations, a great sense of darkness has fallen across the world at the unfolding tragedy in Ukraine," he said.
"The hearts of the Irish people go out to all of those who are suffering from this completely unacceptable, immoral and unjustified violence.
"This violence must stop. Troops must be withdrawn by Russia. The rise of militarism must end. Full humanitarian access must be given to all civilians in need.
"I call on all those inflicting this violence to reflect on that great principle that is lodged in the words of the Universal Declaration of Human Rights, and its affirmation that “recognition of the inherent dignity, and of the equal and inalienable rights of all members of the human family, is the foundation of freedom, justice and peace in the world”.
"I call on everyone to use the tiny glimmers of hope which we have seen to bring this dreadful nightmare to an end and restore peace."