Floyd Mayweather Jr asked his followers to join in a caption competition. Conor McGregor opted for a different approach.

McGregor and Mayweather have spent the latter half of 2016 posturing at each other amid reports of a cross-combat mega-fight, with the UFC lightweight champion the latest to sound off on Saturday.

Undefeated boxing legend Mayweather invited his 14 million Instagram followers to caption a video of McGregor suffering his first submission loss to Nate Diaz.

'Money' Mayweather offered $10,000 for his favourite, yet to be revealed.

And McGregor also looked to live up to his 'Notorious' moniker as he took to social media to respond.

The Irishman, with an accompanying picture of the pair, wrote: "I am going to break his face."

McGregor has been awarded a boxing licence for the state of California and has claimed that the ongoing flirtation with a bout was sparked by Mayweather, who retired from action after taking his pro record to 49-0 against Andre Berto in September 2015.