Floyd Mayweather Jr. put on an open training session in Las Vegas but made a surprise admission ahead of his bout with Manny Pacquiao.

Flanked by his own camp and the media, the 38-year-old went through a workout at his Mayweather Boxing Club in what was the last scheduled public appearance in advance of his fight against Pacquiao on May 2.

After the Pacquiao showdown, Mayweather has one more fight to fulfil the sixth and final instalment of his multi-million dollar Showtime pay-per-view contract – and, while he confirmed that he would fulfil that obligation, he also made a surprising admission.

“I'm pretty much done with all this,” Mayweather was reported as saying by the Daily Mail.

“It's not fun like it was back then. It’s a business now. I don't really enjoy it any longer.”

The welterweight bout, which has been five years in the making, is the richest in boxing history and Mayweather had previously claimed the "world would stop" for their bout.

"May 2 - the world stops. Mayweather v Pacquiao is the biggest fight in history," Mayweather said.

"This is a fight that the world can't miss. I'm in the gym working right now, pushing myself to the limit because I never wanted to win a fight so bad in my life."

However, he insists that his career should not be judged on one fight.

“One fight won't define my legacy. What about the 47 I've already won? It's an important fight. It wraps everything together – the money and my boxing.

“But if one fight defined everything this would be the only one I'd have needed.”

Mayweather and Pacquiao faced off for a press conference last month but have since retreated to their separate camps to prepare for the highly anticipated clash.

Pacquiao will hold his own public workout on Wednesday in Los Angeles.

Mayweather's showing was a light effort built for show and he did not do much talking as he worked the speed bag but occasionally offered words to his camp.

Surrounded by photographers, Mayweather delivered body shots to a sparring partner who wore body armour but did not throw any punches back. He then worked a body bag and seamlessly went through a series of light exercises.

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