When Katy Perry cries in Beijing

Katy Perry cried.

On a recent Sunday afternoon, the pop superstar attended a rehearsal of the China National Orchestra, the country's leading traditional folk music performance group, in Beijing.

When more than 90 Chinese musicians from the orchestra played her hit song, Roar, with ancient Chinese instruments like the guzheng (Chinese plucked zither), erhu (two-stringed bowed instrument) and pipa (four-stringed plucked instrument), she sat at the back of the theater, wiping her tears.

"I have never heard such beautiful music. It's very spiritual. I am so touched," she said onstage to the orchestra's musicians. "This experience is definitely a highlight of my trip to China."

She also showed great interest in the other piece played by the orchestra, Silk Road, during the rehearsal.

Perry, known for her bubbly, fun-loving hits, such as Teenage Dream and Firework, was dressed in a light green cheongsam, accompanied by a pair of high boots.

She says she has always been very interested in Chinese culture.

"I bought this dress a long time ago but I didn't find a proper occasion to wear it. I love the color and design. I think this is the perfect time for me to put it on during my very first trip to China," she said.

Xi Qiang, director of the orchestra, gave the 29-year-old star a xun (Chinese vessel flute). In return, Perry gifted her Baby Taylor acoustic guitar, which has her jewel-encrusted signature.

She was surprised when she was told that all the instruments onstage are more than 1,000 years old and said that she looked forward to cooperating with the China National Orchestra.

"If you come to perform in Los Angeles, we can do Roar together," she said to Xi.

According to Xi, Universal Records, which the artist is signed to, initiated the adaptation of the chart-topping song, Roar, two weeks ago. Zhao Dongsheng, an established composer from the China National Orchestra, re-arranged the song.

"Zhao's adaptation makes Roar sounds good with traditional Chinese instruments. It makes the best use of those ancient instruments while maintaining the beat of the original song. It is a good example of mixing the musical forms of East and West," Xi says.

It's not the first time the orchestra has done such a crossover cooperation with musicians from different fields. They have also adapted Taiwan pop singer-songwriter Jay Chou's hit song Chrysanthemums Terrace into traditional Chinese music and played with renowned cellist Yo-Yo Ma during their tour around the United States.

"Those crossover performances enable traditional Chinese music to connect with today's audiences. We will play our adaptation of Roar during our future tour abroad, which will take us close to international audiences."

The day before the event, Perry performed for the first time ever in China as the special guest at the 2014 Infiniti China Brand Festival at the indoor Olympic Stadium in Beijing. She closed the gala with five songs, including Roar and Teenage Dream. The demanding artist also flew her 50-member production team to Beijing to guarantee the quality of her debut show in China.

Universal Records says it is planning to bring the star to China again during her world tour from 2014 to 2015 since she has a huge fan base in the country.

Roar, the first single from her latest album Prism, topped the Billboard Hot 100 chart for two weeks.

She says Roar is about finding inner strength and not turning into a shell when faced with struggles.

The message she wants to express through her songs, she says, is always what she learns and observes from life.

"I put all my emotions into my songs��the happy things and the vulnerable moments," she says. "And when I come to China, I am so happy to know that I have so many fans here sharing my music."