President Barack Obama and Republican Mitt Romney will go head-to-head in front of 60 million viewers tonight in the final TV debate before the US presidential election.
This election is so close that it will be won and lost on the tiniest of margins.
With just over two weeks to go, the latest opinion polls show Obama and Romney neck and neck - on 47% each. That leaves just 6% undecided.
Many states almost always vote the same way which means the election should be decided by voters in just nine states out of 50.
This debate is all about America's relationship with other countries.
Watch Ricky's report about the fight to become the most powerful man in the world.