This could be the most exciting featherweight championship fight in MMA history.
It could also be one of the closest.
While some may believe Aldo's striking alone is enough to give him the edge, Edgar has never been stopped in his MMA career and may be faster than any opponent that Aldo has ever faced.
This fight could go down to the judges.
Here are the reasons why they could have a very difficult decision to make.
Both Frankie Edgar and Jose Aldo are fighting in their seventh straight title fight tonight.
Both men have taken two very different roads to get to this point, though.
Aldo has been featherweight champion the whole time, spanning his title reign from his 2009 WEC win over Mike Brown.
Edgar, on the other hand, fought his way through the lightweight ranks to become UFC lightweight champion in 2010.
While Aldo has not fought the same man twice during his reign, Edgar has only fought three men in six fights.
This is a fight where the fighters' styles and approach could make the difference.
Edgar is known for his fast-paced boxing, wrestling and having a ton of heart.
Aldo, on the other hand, is one of the best strikers that has ever come in the UFC.
Although you may think Edgar has his best shot on the ground, Aldo has some of the best takedown defense in the game today.
If Edgar does get the fight to the ground, just how much damage can he truly do and how much damage will he have to take before he can get the fight there?
We can assume that Aldo will try to keep the fight standing. But Edgar can take a shot and may be the fastest fighter that Aldo has ever faced.
If Jose Aldo performs well in tonight's fight, he'll say there was no ring rust.
If he does not perform as well as he likes or he loses, you will hear ring rust come out of someone's mouth.
Aldo has not fought since January 14, 2012 when he defeated Chad Mendes.
Aldo was set to fight later in the year, but injuries to his original opponent, Erik Koch, then himself forced him to sit out the rest of the year.
In the time that Aldo has sat out, Edgar has stayed active.
He fought Benson Henderson twice and was preparing to step in for Koch before Aldo got injured.
Edgar may seemed like the man that will be better prepared, but Aldo is a professional, and should be just as ready despite not fighting in a year.
It is remarkable what Frankie Edgar was able to do at lightweight.
Edgar was always the smallest fighter, but simply outworked his opponents.
Now Edgar has the chance to fight at what is truly his natural weight class.
But never fighting at featherweight could be a gift and a curse.
Not to take anything away from Edgar's experience, but Jose Aldo is not an opponent you just walk right into.
Edgar has never faced an opponent with the striking level of Aldo. Even though he is dropping down a weight class, he still is not the biggest fighter in the division.
Although Frankie Edgar has had some close calls, he has never been knocked out or submitted.
Aldo has only lost once, and that was by submission back in 2005 before he came to the WEC.
We know Edgar has an iron chin and a ton of heart, which keeps him into fights after being hurt badly.
We have yet to see Aldo really hurt, though.
Mark Himinick put Aldo through the most danger he's been in when he took him to the ground in their fight.
But Aldo survived and won the fight.
It truly is a tough fight to call when both men are extremely hard to finish.