It will be a return for Christie to the prime-time stage after failing to qualify for the Fox Business prime-time debate last month. Christie has seen a resurgence in recent weeks, particularly in New Hampshire, a key state for his campaign.
Paul, who was in danger of being removed from the main stage, was saved at the 11th hour by showing viability in Iowa in a Fox News poll released Sunday morning.
Podium order was determined by the average of the national polls from November and December.