(Image credit: Gabe Ginsberg/Vegas Kool)

Celebrity guests and VIP's of a popular Las Vegas steakhouse can now eat their meat with a very sparkly, expensive knife.

"Female friendly" steakhouse STK has collaborated with celebrity jewelry designer Jason of Beverly Hills on a set of diamond- and pink sapphire-encrusted knives. The set, which includes one $18,000 diamond knife and a new $12,000 pink sapphire knife, is only available at the restaurant's location in the Cosmopolitan hotel.

Jesse Mancha, general manager at the Jason of Beverly Hills location in the hotel, said the new knife contains "300 full-cut pink sapphires set into a signature steak knife." The 6.5 carats of sapphires took a craftsman 20 hours to hand set into the stainless steel knife.

(Image credit: The One Group)

"The original idea came about over drinks with Jason, myself and Tyra Bell-Holland, director of marketing and events," said Mancha.

Jason had created a whole dinnerware set for the royal family of Saudi Arabia as a wedding gift. The dinnerware set included diamond plates and was one of the jeweler's first big projects.

He "wanted to bring it to diners in general," said Mancha. "After the first diamond knife was created, Tyra was telling us about issues that everyone wanted to dine with the knife but there was only one knife."

The sapphire knife was created to complement the set and designed with VIP couples in mind. Leann Rimes and Eddie Cibrian used the knives when they celebrated Valentine's Day together at the restaurant.

Musical group Foster the People, known for their hit song "Pumped Up Kicks," went around sharing the knife during dinner.

After their meal, they came to the store in the hotel hoping to purchase it, explained Mancha. The knives aren't readily available to purchase but "we could make it custom for them."

Singer Gavin Rossdale and his band, Bush, enjoyed a dinner at STK last year after a private show at the hotel. The singer used the knife to cut his Waygu beef filet.

"We ask any guest presented with the opportunity to use either of the knives to kindly sign our knife guest list…fun for them and for us it memorializes their experience at STK," said Tyra Bell-Holland.

Rossdale signed the book writing it "cut like a knife but glitters like the best girl."

Who decides who uses the knives? "It's really a combination of minds here at The ONE Group…but we're in the hospitality business…we treat everyone's knife like it's diamond-encrusted," said Bell-Holland.

Jason of Beverly Hills designed Jessica Alba's engagement ring as well as Nick Cannon's anniversary gift for wife Mariah Carey.