"Voting is a right we have won, and we will not let it be taken from us. We must be at polling stations tomorrow, across the country as well as outside it. The will and the power of the people cannot be defeated," Georgescu told the Realitatea broadcaster.
The politician pledged to challenge the Constitutional Court's decision.
"The ballots have already been printed, but the Constitutional Court is trying to overturn the process without legal grounds for doing so."
According to the November 24 election's results published by the Central Election Commission, Georgescu won the first round with 22.94% of the vote. The leader of the liberal Save Romania Union, Elena Lasconi, who favors a partnership with NATO and the United States, came second with 19.18%.
The second round of elections was scheduled for December 8. However, the Constitutional Court ruled on Friday to cancel the results of the first round, paving the way for a rerun. The Romanian government must now set the date of a new presidential vote. Both Georgescu and Lasconi criticized the ruling.