In the U.S., Wendy's (WEN) serves such signature items as fresh, square ground-beef patties and the Frosty. In Japan, where the fast food chain is looking to expand, it's adding decidedly more upscale fare to its menu -- namely, lobster and caviar.

The Lobster Surf & Turf Burger and the Premium Caviar & Lobster Sandwich will be offered for a limited time at Wendy's Tokyo locations -- one in the fashionable Omotesando neighborhood, home to many luxury shops, and a second opening Aug. 17 in the Roppongi Hills complex.

"Each sandwich is priced at ¥1,280 or approximately US$16.28," reports Burger Business. "Or go big (¥1,580/$20.11) for the Garden Sensation salad with lobster and caviar." The dishes use Omar lobster meat imported from Canada.

"These premium specialty sandwiches are really designed for the Japanese consumer," explains Bob Bertini, a Wendy's spokesman. "We have a joint venture in Japan and as part of that we have kitchens that help design sandwiches that make particular sense for that market."

"Seafood is a huge part of Japanese culture and diet, and this just makes sense."

The Japanese restaurant market is intensely competitive, Bertini said, "and this is a way to help differentiate ourselves from other chains in the country." He added that there are no plans to introduce a similar sandwich line in the U.S., where Wendy's entrées don't tend to top $5 or $6.

Wendy's left Japan 2009, and reentered in December 2011 with a new slate of ritzy offerings, including a $16 burger topped with foie gras and truffle sauce.