The Irishman publicly praised the president on Twitter, while Trump congratulated him for his win in UFC 246 on Saturday night.
Mayweather retired for a third and final time after defeating McGregor in August 2017 but his latest Instagram post suggests a comeback may be on the cards.
The Irishman is a heavy favorite to come out on top in Las Vegas in his first professional fight since October 2018.
President Donald Trump was booed on Saturday night when he arrived at Madison Square Garden to attend Ultimate Fighting Championship (UFC) 244, but one Fox News host believes that Trump wanted this reaction from the crowd.
The negative reception to the president came in spite of Trump's early support for the sport who hosted its events when other venues and legislators shunned the UFC.
Numerous videos posted on social media showed the crowd booing when President Donald Trump arrived for the UFC fight at Madison Square Garden in New York City.
Till said he still has "unfinished business at welterweight" despite his struggles to cut weight in the past.
The 25-year-old "Sorry" singer claimed he was joking about fighting the Hollywood star.
The 25-year-old singer took to Twitter to announce he wanted to take on the 56-year-old action movie star in a UFC clash.
The Irishman announced his retirement from MMA via a post on his Twitter account on Monday night.
The 33-year-old won the belt at UFC 217 in November 2017.
McGregor allegedly left the famed Fontainebleau Hotel with a fan and smashed their phone when the fan tried to take his photo.
"You accomplished the main goal: You won the fight, with confidence and dignity," Putin told the fighter.
UFC lightweight fighter Nik Lentz gave a bizarre "shoutout" to Judge Brett Kavanaugh Saturday just hours after the controversial Trump nominee was sworn in to the Supreme Court.
The 24-year-old had a ghost writer take down the account.
Anthony Joshua could earn as much as $50 million per fight if he switches to MMA.
"Honestly I was just praying, 'Lord, please do not kill me,'" VanZant said about a 10-pound cut in a single day.
Daniel Cormier has been reinstated as the new heavyweight champion.