Floyd Mayweather pulled off the ultimate feint ... the boxing legend took friend, businessman Robert Smith to look at property -- at least, that's where the billionaire investor thought they were going -- but in reality, the 50-0 legend delivered Smith to his surprise 60th birthday party!
"When Robert walked into his house he was shocked to see us all there. He was really surprised and had no clue that his family threw him a surprise party," Mayweather tells TMZ Sports.
And, the Palm Beach, FL party was awesome ... the theme was James Bond: 0060, to commemorate Smith -- who Forbes estimates is worth around $8 billion -- for turning 60 years old earlier this month.
Everything from the decorations to the cake was Bond-themed!
Robert is a big collector of Bond writer Ian Fleming first editions ... hence the theme.
We're told only 60 of Robert's closing family and friends were in attendance ... and cell phones were taken at the door.
Aside from being friends, Smith is also an investor of Floyd's docuseries, "The GOAT." The property Smith thought he and Floyd were viewing was supposed to be a potential shooting location for the future series. Producer Deon Taylor, Floyd and Robert's partner, was also in the building.