The fight is expected to generate a purse of up to $400m and the hype ahead of the clash, which has taken years to arrange, is off the scale.
But what time will the action start and how can UK fight fans see the bout?
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What time is the fight?
The fight it taking place at the MGM Arena in Las Vegas. Nevada is eight hours behind the UK, which means that fight fans will have to stay up until the early hours of Sunday 3 May to watch the event.
Mayweather and Pacquiao are scheduled to enter the ring at 8pm in Las Vegas, which is 4am in the UK.
Is there an undercard?
Whether or not the fight gets underway on time depends to an extent on the undercard, and there are six fights taking place before the main event. The first fight is scheduled for 3pm in Vegas, but the TV coverage does not begin until 6pm local time and only the last two fights on the undercard will be screened.
The first sees WBO featherweight champion Vasyl Lomachenko face Gamalier Rodriguez, the second pits WBC super bantamweight world champion Leo "El Terremoto" Santa Cruz against Jose Cayetano.
However, Yahoo suggests these fights are unlikely to delay the big one as both reigning champions are likely to win.
"With both undercard bouts looking like mismatches, it isn't hard to imagine each fight ending early via KO. Maybe even really early. In that case, it's reasonable to expect a lot of pre-produced filler or a lot of live analysis until the main event. Another possibility: the undercard bouts could be stretched out, with filler content placed between them," it warns.
How can I watch the main event?
First up, be grateful you are not in the US, where HD pay-per-view packages cost $100. In contrast, watching on Sky Box Office in the UK will only set you back £20 if you book before Friday night. The cost increases to £25 after that.
The event can be booked using a Sky remote or online.
What if I don't have Sky?
National chains like Walkabout and Rileys will be showing the fight, as will many other venues.
Again, be grateful you are not in the US. Bars are having to fork out thousands of dollars to show the fight, and an army of spies has been employed to report anywhere illegally showing the fight. And don't be tempted to head to Vegas for a slice of the action – the only place you can watch the bout is at resorts owned by MGM, where you will have to cough up $150 to watch on TV – no other hotels, bars and casinos are allowed to screen the fight.
Will it be worth it?
Mayweather v Pacquiao has taken years to arrange and is the most-hyped fight in history. Tickets are changing hands for more than $100,000. The good news for boxing fans is that an early knock-out is not expected and most experts believe the fight will be decided on points.
Filipino Pacquiao may have more support than the brash but brilliant Mayweather, but bookies and most pundits, including Ricky Hatton, are of the opinion that the American has the best chance.
"Opinions are pretty spit with this fight but the bookmakers believe that unbeaten Vegas boxer Mayweather will have the upper hand and has been made favourite for the fight," says the Daily Mirror.
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