The pair hit the scales tonight in Las Vegas’s T-Mobile Arena ahead of the twelve round light middleweight (154lbs) fight tomorrow night at the same venue.
The weigh-in is due to start at 11:00pm (Irish time), although the pair aren’t expected to take to the scales until a little while after this
At 3:00pm local time, it is relatively late for a weigh-in – which would look to be more of a hindrance to McGregor than Mayweather.
While Mayweather has been out for nearly two years, the heaviest Mayweather has ever came in at was 151lbs against Miguel Cotto, who also fights tomorrow night, way back in 2012.
The atmosphere tonight is expected to exceed that of the actual fight tomorrow, with costly tickets proving a barrier to the thousands of Irish fans who have made the trip over to Sin City.
Watch the weigh-in live below: