Manny Pacquiao and Juan Manuel Marquez are adding a fourth act to their legendary rivalry, announcing plans for another showdown.

The historic fourth bout between the talented fighters will take place in Las Vegas on December 8, with hopes of once and for all ending the argument as to who is best.

"This fight is going to be a great fight because I want to erase all doubt for the fans of boxing," said Pacquiao, referring to the ongoing debate as to the winner of the previous three bouts.

"There are so many people saying if I really won the fight. I said, 'Yes, I won the fight no doubt.' Marquez claims he won the fight. So, I think something is wrong," he continued.

For Marquez, the fourth opportunity to climb inside the ring against Pacquiao, who is arguably boxing's biggest draw, is a chance to set the record straight.

"People say why again, why again with Pacquiao. I said because I want to prove who is better," said Marquez, at the news conference.

"I want the referee to raise my hand. Finally, I am training very hard for December 8. I will be ready to fight and I will be ready to win again. Because, I don't like the judges decision because everyone knows what happened in the first three fights. I will train hard and see you on December 8."

If the Pacman beats Marquez, the potential for a superfight against Floyd Mayweather still remains a possibility.