LAS VEGAS -- Floyd Mayweather Jr. says he's coming out of retirement again to fight Manny Pacquiao for a second time in December.

Mayweather posted a video on Instagram early Saturday that showed Pacquiao and him together, reportedly in Japan, jawing at each other over a possible second fight.

Whether the fight will actually happen remains to be seen. There are no promotional barriers between the two men, because Mayweather promotes himself and Pacquiao is a boxing free agent.

Mayweather defeated Pacquiao in May 2015 in a massively hyped fight that was largely panned by most boxing fans. The bout delivered a record 4.6 million pay-per-view buys.

Representatives for the two fighters could not immediately be reached for comment.