Mayweather vs McGregor: Battle of the trash talk

As the world counts down to one of the most hyped fights in history, we take a look at the epic trash talk battle between Conor McGregor and Floyd Mayweather.

As you can see from the video above, there is absolutely no love lost between the Irishman and the American, with both fighters vying for the upper hand in the sledging stakes.

Following the announcement that Mayweather, the undefeated welterweight boxer, will come out of retirement in August to face McGregor, a mixed-martial arts superstar, in a first-of-its-kind cross-trade boxing match, both took to their Twitter handles to seal the deal with a kiss.

And McGregor seized the opportunity to throw the first shot.

The picture is of none other than 64-year-old Floyd Mayweather Sr., a humorous dig at Floyd Jr., who's no longer a spring chicken at 40.

McGregor is 12 years younger, so he's within his right to make all the old man jokes that come to mind. He had already gotten started earlier this week.

Many experts have tipped the American to have far too much class for the Irish UFC star in a 12-round boxing contest.

But UFC boss Dana White says he is sure McGregor has the tools to shock the fighting world.

"Even though it's a straight boxing match, Floyd Mayweather is 40 years old and he hasn't fought in over two years," White told Fox Sports News.

"If you want to look and see if there's any kind of chink in the armour, it's against southpaws.

"Conor McGregor is 28 years old, he is a southpaw and when he touches people, they go to sleep.

"So the question is in a 12-round fight, can Conor McGregor touch Floyd Mayweather."

Mayweather, 40, will come out of retirement and put his flawless 49-0 boxing record on the line against McGregor in the ring.