Luxury automotive brands partnering with fancy watch brands is hardly uncommon nowadays, but seldom are the timepieces so integral to the car. This latest pair of watches, made by Bovet 1822, have been designed to also function as the clock in the Rolls-Royce Boat Tail.

Made in his-and-hers styles and designed to the exact specifications of the couple who ordered the Boat Tail (who may or may not be Jay-Z and Beyonce), the watches are more accurately called timepieces. That’s because their design allows them to be used as watches, as the clock on the Boat Tail’s dash, as pocket watches, pendants, or table clocks.

Designed specifically for the car, the watches slot into a receptacle on the car’s dashboard. Their dual purpose, though, meant a few engineering challenges for Bovet 1822 to solve. First and foremost, as a piece of a car, the timepieces and holder had to be tested to automotive-industry standards for vibration and crash safety, which the watchmaker says has never been done on a mechanism of this kind before.

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Its place in the Rolls-Royce also meant that there were weight limitations. To meet those demands, the watches have 44 mm white gold cases of an entirely new design.

As for the horological challenges of creating a watch that’s also a clock, Bovet 1822 decided to use a tourbillon mechanism to counteract the forces of gravity that conspire to weigh down traditional watch mechanisms and pull them out of accuracy when they remain stationary. The tourbillon mechanism means that the timepieces do not rely on the motion of their owners’ arms to stay in sync with the passage of time.

To celebrate all that work, both timepieces have been designed with the car they’re going into in mind. They feature matching front dials with the same Caleidolegno veneer found on the aft deck of the Boat Tail. They are also completed with the owners’ names, which appear to have been edited out in these pictures.

For the lady, the timepiece is ornately engraved and filled with blue lacquer. It is then decorated on the reverse side with an ornate miniature painting of a flower bouquet on a mother-of-pearl dial.

For the gentleman, the timepiece is highly polished and the reverse side features an aventurine dial with the celestial arrangement of the night sky over the place of his birth on the day of his birth. A patented Amadeo case is what allows them both to be worn with such versatility.

“I am so proud of the BOVET 1822 team, who worked in tandem with their counterparts at Rolls-Royce to produce something truly spectacular,” said Pascal Raffy, owner of Bovet 1822. “The owners of the coachbuilt car, and these bespoke timepieces, are personal friends, as well as valued collectors of BOVET 1822. It was important to do the very best for them – two completely unique pieces that are unlike anything we have ever done before.”

No price has been disclosed for these unique watches, but Bovet 1822 did reveal that they were the result of 3,000 hours of work.