UFC superstar Conor McGregor has continued to fuel talk of a cross-sport fight with Floyd Mayweather Jr.

McGregor created waves on social media after posting footage of himself sparring in a boxing ring on Instagram. He wanted to show everyone that he's seriously preparing for a boxing match with Mayweather.

The fight is still considered a pipe dream to most because of the enormous amount of red tape surrounding it.

The primary sticking point is McGregor's exclusive contract with the UFC.

McGregor believes that he can use the Muhammad Ali Act to step around his contractual ties to the UFC.

UFC President Dana White has practically promised a lawsuit if McGregor attempts to step around them to fight Mayweather.

According to White, there is no way possible that McGregor can fight Mayweather without the involvement of the UFC.

White attempted to get his company involved by offering both fighters $25 million each for a pay-per-view battle. Mayweather laughed at the offer, as did McGregor. Both Mayweather and McGregor have been asking for at least a $100 million.

Mayweather, who retired from boxing in September 2015, says McGregor is the only fight that would tempt him to return to the ring.

"Most likely the fight between me and Conor McGregor will happen," Mayweather said to Sky Sports. "That's the only fight that will get me back in the ring. He's going to do a job on his side and we are going to do a job on my side and hopefully all the fans in the UK come over and support me.

"I don't know (when it will be), I need to communicate with my team, the fight hasn't been made yet, but it is all about entertainment so hopefully we can make it happen. I believe the next time I step into a combat arena will be through the ropes wearing 10-ounce or eight-ounce gloves. I believe so," he said.