Dwayne Johnson made his first-ever Met Gala appearance Monday night and brought a $3.3 million Jacob & Co. Billionaire III along for the ride. The 18-carat white gold rectangular skeleton watch, set with 714 white diamonds totaling 129.61 carats, is one of the most expensive timepieces ever spotted on the museum's steps, according to GQ . The watch is built to a scale that matches its price. At 54 millimeters in diameter, it dwarfs the 36-to-40mm range that typically defines men's watches today, and even the movement itself measures 40.05mm wide. Of the 714 diamonds, 504 are set into the bracelet alone, with 77 in the case, 76 in the inner ring, and 57 across the movement bridges. Jacob & Co. produced only 18 pieces, with pricing listed as available on request. Jacob & Co.…