There are watch pendants and watch brooches and watch rings, but Rihanna apparently had a different idea: a watch choker.

So the Barbadian singer, actress and businesswoman turned to Jacob Arabo of Jacob & Co., the New York City jeweler and watchmaker who has created other pieces for her over the past 10 years. (Remember the red diamond-enhanced wristwatch she wore for the Super Bowl halftime performance in February? That was a Jacob & Co. design called Brilliant Skeleton Northern Lights.)

“Rihanna has always been fond of us,” Benjamin Arabov, one of Mr. Arabo’s three sons and the company’s chief executive, who spells his family name differently than his father does, said in a video interview. “She has an edgy personality and creates her own path, whether in fashion or music or her beauty line.”

He liked the idea of creating a watch choker, he wrote in a later email, because, “as a brand, we have a reputation for doing things differently, outside of traditional watchmaking.”

The company sent several of its watches, in a range of prices, to Rihanna’s stylists, Jahleel Weaver and Amir Dayi. And in true @BadGalRiRi style, Mr. Arabov said, Rihanna “chose the most expensive” — the 47-millimeter Brilliant Flying Tourbillon — which, he noted, “was all iced out.” (It retails for $670,000.)

The watch is adorned with 338 baguette-cut white diamonds, totaling 30 carats, which are distributed over the dial, crown, and 18-karat white-gold case. There also are 338 more diamonds set on the watch’s flying tourbillon movement.

“We had concerns about the weight of the watch,” Mr. Arabov said. “It’s white gold and a tourbillon, so it’s not the lightest watch on the market to wear on the neck.”

But it was deciding how to close the strap, made of black leather embossed to look like alligator, that turned out to be the biggest challenge. “We considered using a buckle system, but ended up with a Velcro system,” he said, explaining that the adjustable strap made it easy for the singer, who is pregnant, to alter the fit.

Rihanna debuted the watch choker during Paris Fashion Week, when she sat front row on June 20 for Pharrell Williams’s first runway show as men’s creative director at Louis Vuitton. “It was very exciting for us,” Mr. Arabov said, adding that, by his company’s estimate, about 150 million people saw the news and social media coverage of the event.

The jeweler has 18 more Brilliant Flying Tourbillons ready to be turned into chokers, although Mr. Arabov acknowledged it is not an easy way to check the time. “It’s more of a fashion statement she was pushing,” he said, adding, “She picked such a huge stage to do it.”