Undefeated American fighter Floyd Mayweather Jr. seems to be enjoying his retirement as he was reportedly seen recently singing with pop sensation Justin Bieber in Bora Bora, an island in French Polynesia.

TMZ Sports said that the close friends had a duet last Saturday during a karaoke night in the said island where he and "The Money" were vacationing over the weekend.

"We're told the two stopped by their hotel's bar during karaoke night on Saturday ... when Justin decided to treat everyone to -- of course -- his own song, 'What Do You Mean,' before getting on piano and playing 'Let It Be,'" added the same report.

On Mayweather's Instagram account, the boxer posted a video of him and Bieber counting money with him saying later on social media that money does not make him, instead he makes money.

According to Daily Mail, the friendship of the singer and the boxer started last May 2012, when Bieber accompanied "The Money" as he walked to the ring before his fight versus Miguel Cotto.

Now that Mayweather has declared that his September win against Andre Berto was his last, it seems that he is already enjoying the perks of his retirement. He ended his career with a 49-0 record.

"It's my time to hang 'em up. I've been in the sport for 19 years. I've made great investments and I'm financially stable. Records are made to be broken. Maybe we can find another Floyd Mayweather. Now I want to a spend time with my family. I am leaving the sport with all my faculties. I'm still smart, I'm still sharp. I've accomplished everything," Mayweather was earlier quoted by Telegraph as saying.

He also clarified that he will not anymore fight one more fight despite prodding from fans.

"My career is over. It's official. There's nothing left to prove in the sport of boxing," he added.

Despite making a world record with no losses for his 49 fights, New York Post noted that it is still debatable if Mayweather can really be called "The Best Ever."

"His legacy will be debated by those who believe his 49-0 record with 26 knockouts qualifies him as 'The Best Ever' and those who believe that he hand-picked his opponents at their weakest and was boring to watch," the same report added.

A boxing insider even told the New York Post that Mayweather was successful in establishing an image for himself.

"He's a unique personality. He wanted a certain image and he created it," the insider noted.

The so-called retirement for Mayweather, as sports analysts see it, is already questionable since in 2007 he already said that he will retire from boxing but returned after 21 months.