BEIJING - Yao's Chao Gan, a popular traditional Beijing restaurant with 22 years of history, hosted a special guest on Thursday - United States Vice-President Joe Biden.

According to the 57-year-old manager Yao Yan, police officers and Secret Service members inspected the shop at 10 am, right after she received a phone call from the US embassy in China alerting her of the special guests.

"It surprised everyone here indeed," Yao said.

Newly instated US Ambassador Gary Locke and his wife, Mona, joined Biden and his granddaughter for lunch.

Biden and his entourage arrived at Yao's Chao Gan, which translates to stir-fried pork liver, at 1:30 pm. Even though he doesn't speak Chinese, he still shook hands with customers and posed for photos.

Biden's friendliness impressed the host, who said Biden also introduced his granddaughter to customers.

The shop prepared a separate room with a big table that sits 10 people. Delicate dinner sets with beautiful flower decorations were placed at each place setting. But the American guests insisted on sitting in the main dining room among the other customers.

Five of them sat at one table and ordered five bowls of Beijing noodles with soybean paste, 10 steamed buns, smashed cucumber salad, mountain yam salad, shredded potatoes and Coca-cola. The meal cost 79 yuan ($12.37).

"Biden seemed to really enjoy the Beijing noodles with soybean paste, and they finished all of the dishes they ordered," the manager said.

Yao Long, in his 30s, was assigned to wait on the US officials. He said when he delivered the food the vice-president was talking to the Lockes.

"I didn't understand what they were talking about, but it seemed like they were having a very good conversation," the waiter said.

The vice-president paid for lunch with 100 yuan, insisting the restaurant keep the change as a tip.

"I never though he would pay for lunch himself," Yao Long said. He was also surprised when Biden pulled out a 100-yuan note from his pocket. "He is using renminbi!"

Biden suggested taking photos with every restaurant employee after lunch, including the managers and the cooks.

"Although some of our cooks wore chef uniforms with many oil stains and smells, he was still every happy to embrace them and take pictures together," Yao Yan said, adding that Biden invited them to the White House if they visit the US in the future.

Yao's Chao Gan is a family business, featuring traditional Beijing-style food such as stir-fired pork liver and pigs' intestine. It is located in Beijing's Dongcheng district, near the Drum Tower.

Yao Yan's father founded the restaurant in the late 1980s, and she now manages the shop with her brother and sister.

The two-story restaurant is about 300 square meters (3,000 square feet) and can seat about 100 guests at a time. It is well-known among Beijing residents for its snacks.

The restaurant started an official page on Sina Weibo, a Chinese micro-blogging website, one hour after the Americans left. It had attracted almost 250 followers in a few hours.

As some Weibo followers suggested, the restaurant is considering adding "vice-president noodles" to its menu, as a Shanghai restaurant did after a visit from the former US President Bill Clinton in 2006.

However, some people were questioning if the restaurant offered the vice-president a lower price than what's advertised. Some netizens said they paid 15 yuan for the noodles, while the restaurant only asked for 9 yuan on Thursday.

A Weibo user named Miao Genpei said he would love to order the same dishes.

"As long as it is 79 yuan for all the dishes, I'd love to tip them 21 yuan as well," the netizen said. "The price for Biden's lunch is a miracle."