Although Floyd Mayweather Jr. has yet to announce his plans for 2015, his father has no doubt that a fight against Manny Pacquiao will happen.

"It's gonna happen. That fight's gonna happen. Trust me," Floyd Mayweather Sr. told fighthype.com. "That fight's definitely gonna happen. It's a fight for the world, man, right there. It's the biggest fight that has ever been in life, so like I said, man, that fight's gonna happen."

Mayweather Sr. said his son never told him that the fight was in his plans, but with his son saying that he will retire after finishing the two fights left on his six-fight Showtime deal, he believes all signs point to the megafight with Pacquiao.

Floyd Mayweather has repeatedly said that he plans to retire after his contract with Showtime, which has two fights remaining, comes to an end. Al Bello/Getty Images

"[I'll] tell you right now, he never told me the fight's gonna happen, but ... the fight's gonna happen," Mayweather Sr. told the website. "You mark my words, and we'll see."

The 37-year-old Mayweather Jr., who is 47-0 with 26 knockouts and holds the welterweight and junior middleweight titles, has yet to divulge his future plans other than he expects to fight somebody in May.

"I'm gonna go and talk to my team and see what the future holds," Mayweather said last month after his second victory over Marcos Maidana. "I don't know who I'm fighting in May, but I expect to fight in May. Manny Pacquiao needs to focus on the guy in front of him. Once he gets past him, he can look to the future. If the Pacquiao fight presents itself, let's make it happen."

"That fight's definitely gonna happen. It's a fight for the world, man, right there. It's the biggest fight that has ever been in life." Floyd Mayweather Sr., on prospect

of his son fighting Manny Pacquiao

The 35-year-old Pacquiao, who next defends his welterweight title on Nov. 22 against Chris Algieri in Macau, China, has said that a fight against Mayweather "could happen" in 2015. He even took a few jabs at Mayweather last month on Twitter, saying, "He acts like an uneducated person" and that "he should fear God."

Pacquiao promoter Bob Arum said recently that HBO and Showtime/CBS have been holding talks about working together on a joint pay-per-view.

It remains to be seen whether a deal can be made -- it has gone unmade for years despite intense public demand -- but count former champion Sugar Ray Leonard among those who want to see it happen.

"They should fight. ... That fight would be huge," Leonard told Fox 11 Los Angeles last month. "I think fans are starving for excitement. Fans are starving for competition, evenly matched fights. But it would be huge."

Information from ESPN.com's Dan Rafael and The Associated Press was used in this report.