The Sinn Fein leader says a vote on Irish unity could happen in the next five years, following its historic showing in the Northern Ireland election.
Counting continues this morning in the Assembly elections.
Sinn Féin clearly topped the poll when it came to percentage of the vote and will likely be the largest party in Stormont when the counting is done.
The party didn't mention a referendum in the run up to the Assembly vote, instead it focused on the cost of living crisis in the North.
But speaking to CNN, Mary Lou McDonald says planning for Irish unity needs to start now:
"I believe, within this decade, we will witness constitutional change on the island of Ireland and it is my absolute determination that that change will be entirely peaceful, entirely democratic and orderly. So, we have been saying to the government in Dublin and indeed in London, that the preparation for constitutional change in Ireland needs to begin now".
